Prevent random floats from occasionally being greater than 1.
Prevent random floats from occasionally being greater than 1.

Previously, gen_f64 could generate numbers as high as 1.0000000002328306
in the case that u3 was 4294967295.0f64 and u2 was nonzero.  This change
divides the random numbers by 2**32 instead, effectively concatenating
their bits as apparently intended.  (Bonus fix: const.)

The comments are updated to be more specific than "random float"; note
that this can still generate 1.0f64 (P = 2**-54) due to rounding.

avdi/rust,miniupnp/rust,zachwick/rust,erickt/rust,mdinger/rust,kwantam/rust,mitsuhiko/rust,hauleth/rust,quornian/rust,KokaKiwi/rust,dinfuehr/rust,pelmers/rust,bluss/rand,reem/rust,jbclements/rust,jashank/rust,untitaker/rust,barosl/rust,richo/rust,erickt/rust,aturon/rust,omasanori/rust,rprichard/rust,hauleth/rust,servo/rust,zaeleus/rust,jbclements/rust,kmcallister/rust,vhbit/rust,barosl/rust,ktossell/rust,ruud-v-a/rust,robertg/rust,mihneadb/rust,zubron/rust,nham/rust,rprichard/rust,pshc/rust,hauleth/rust,pythonesque/rust,zachwick/rust,stepancheg/rust-ide-rust,vhbit/rust,sarojaba/rust-doc-korean,victorvde/rust,victorvde/rust,sarojaba/rust-doc-korean,emk/rust,waynenilsen/rand,XMPPwocky/rust,nwin/rust,zaeleus/rust,vhbit/rust,pelmers/rust,aidancully/rust,stepancheg/rust-ide-rust,mitsuhiko/rust,pythonesque/rust,ebfull/rust,miniupnp/rust,zachwick/rust,michaelballantyne/rust-gpu,zubron/rust,kimroen/rust,P1start/rust,fabricedesre/rust,omasanori/rust,fabricedesre/rust,robertg/rust,pythonesque/rust,ktossell/rust,graydon/rust,nwin/rust,nwin/rust,l0kod/rust,mdinger/rust,pelmers/rust,avdi/rust,Ryman/rust,pczarn/rust,cllns/rust,mdinger/rust,AerialX/rust,andars/rust,nwin/rust,jroesch/rust,quornian/rust,aneeshusa/rust,LeoTestard/rust,kmcallister/rust,ktossell/rust,servo/rust,michaelballantyne/rust-gpu,jbclements/rust,zubron/rust,rohitjoshi/rust,bombless/rust,aidancully/rust,jroesch/rust,fabricedesre/rust,hauleth/rust,sarojaba/rust-doc-korean,mihneadb/rust,nwin/rust,TheNeikos/rust,Ryman/rust,pshc/rust,pczarn/rust,richo/rust,aturon/rust,AerialX/rust-rt-minimal,pelmers/rust,quornian/rust,aepsil0n/rust,GBGamer/rust,0x73/rust,zubron/rust,jbclements/rust,kimroen/rust,kwantam/rust,emk/rust,AerialX/rust-rt-minimal,rprichard/rust,jashank/rust,zubron/rust,kimroen/rust,andars/rust,philyoon/rust,robertg/rust,barosl/rust,carols10cents/rust,XMPPwocky/rust,sae-bom/rust,pczarn/rust,dinfuehr/rust,avdi/rust,SiegeLord/rust,mihneadb/rust,mvdnes/rust,rprichard/rust,robertg/rust,XMPPwocky/rust,aidancully/rust,krzysz00/rust,carols10cents/rust,dwillmer/rust,pshc/rust,AerialX/rust,GrahamDennis/rand,nham/rust,TheNeikos/rust,bombless/rust,rohitjoshi/rust,carols10cents/rust,nham/rust,pythonesque/rust,ktossell/rust,kwantam/rust,jroesch/rust,defuz/rust,0x73/rust,omasanori/rust,philyoon/rust,nwin/rust,TheNeikos/rust,zaeleus/rust,zaeleus/rust,dwillmer/rust,reem/rust,seanrivera/rust,mvdnes/rust,aneeshusa/rust,SiegeLord/rust,mdinger/rust,l0kod/rust,bombless/rust,rohitjoshi/rust,avdi/rust,aidancully/rust,P1start/rust,sae-bom/rust,l0kod/rust,krzysz00/rust,gifnksm/rust,KokaKiwi/rust,defuz/rust,SiegeLord/rust,pelmers/rust,AerialX/rust,pczarn/rust,zubron/rust,LeoTestard/rust,pshc/rust,mvdnes/rust,ebfull/rust,jroesch/rust,sae-bom/rust,barosl/rust,aepsil0n/rust,pelmers/rust,michaelballantyne/rust-gpu,reem/rust,jroesch/rust,aepsil0n/rust,rprichard/rust,ejjeong/rust,kmcallister/rust,jashank/rust,dwillmer/rust,dwillmer/rust,ruud-v-a/rust,carols10cents/rust,dwillmer/rust,gifnksm/rust,avdi/rust,mitsuhiko/rust,quornian/rust,cllns/rust,P1start/rust,SiegeLord/rust,servo/rust,aneeshusa/rust,victorvde/rust,pythonesque/rust,philyoon/rust,servo/rust,AerialX/rust-rt-minimal,untitaker/rust,kimroen/rust,emk/rust,vhbit/rust,rohitjoshi/rust,quornian/rust,miniupnp/rust,sarojaba/rust-doc-korean,rohitjoshi/rust,michaelballantyne/rust-gpu,zachwick/rust,mdinger/rust,Ryman/rust,nwin/rust,TheNeikos/rust,Ryman/rust,dwillmer/rust,seanrivera/rust,AerialX/rust-rt-minimal,j16r/rust,ruud-v-a/rust,bhickey/rand,carols10cents/rust,omasanori/rust,gifnksm/rust,michaelballantyne/rust-gpu,vhbit/rust,vhbit/rust,richo/rust,nham/rust,aidancully/rust,pythonesque/rust,mahkoh/rust,l0kod/rust,servo/rust,victorvde/rust,P1start/rust,dwillmer/rust,kmcallister/rust,aneeshusa/rust,rprichard/rust,seanrivera/rust,erickt/rust,KokaKiwi/rust,stepancheg/rust-ide-rust,mahkoh/rust,barosl/rust,ruud-v-a/rust,j16r/rust,jroesch/rust,jbclements/rust,zubron/rust,LeoTestard/rust,LeoTestard/rust,seanrivera/rust,fabricedesre/rust,fabricedesre/rust,XMPPwocky/rust,pshc/rust,P1start/rust,j16r/rust,sarojaba/rust-doc-korean,graydon/rust,zaeleus/rust,j16r/rust,robertg/rust,AerialX/rust,cllns/rust,mdinger/rust,kmcallister/rust,bombless/rust,hauleth/rust,krzysz00/rust,erickt/rust,michaelballantyne/rust-gpu,aneeshusa/rust,aturon/rust,TheNeikos/rust,mihneadb/rust,0x73/rust,mitsuhiko/rust,mihneadb/rust,emk/rust,l0kod/rust,vhbit/rust,kmcallister/rust,aepsil0n/rust,mahkoh/rust,andars/rust,mitsuhiko/rust,victorvde/rust,pshc/rust,quornian/rust,hauleth/rust,TheNeikos/rust,aturon/rust,shepmaster/rand,philyoon/rust,Ryman/rust,ebfull/rust,achanda/rand,AerialX/rust-rt-minimal,aturon/rust,GBGamer/rust,miniupnp/rust,jbclements/rust,pshc/rust,aturon/rust,GBGamer/rust,servo/rust,sae-bom/rust,robertg/rust,mahkoh/rust,jashank/rust,kimroen/rust,reem/rust,LeoTestard/rust,kimroen/rust,ruud-v-a/rust,SiegeLord/rust,stepancheg/rust-ide-rust,l0kod/rust,defuz/rust,vhbit/rust,ktossell/rust,untitaker/rust,untitaker/rust,ebfull/rand,untitaker/rust,GBGamer/rust,SiegeLord/rust,0x73/rust,KokaKiwi/rust,0x73/rust,barosl/rust,P1start/rust,emk/rust,miniupnp/rust,richo/rust,GBGamer/rust,retep998/rand,KokaKiwi/rust,servo/rust,graydon/rust,sae-bom/rust,aneeshusa/rust,Ryman/rust,Ryman/rust,seanrivera/rust,krzysz00/rust,zaeleus/rust,dwillmer/rust,ejjeong/rust,ktossell/rust,P1start/rust,reem/rust,aepsil0n/rust,0x73/rust,ejjeong/rust,krzysz00/rust,mihneadb/rust,jashank/rust,aturon/rust,pythonesque/rust,bombless/rust,jbclements/rust,arthurprs/rand,huonw/rand,nham/rust,emk/rust,graydon/rust,ebfull/rust,pshc/rust,dinfuehr/rust,jbclements/rust,richo/rust,stepancheg/rust-ide-rust,mitsuhiko/rust,mvdnes/rust,mvdnes/rust,quornian/rust,pczarn/rust,miniupnp/rust,mvdnes/rust,untitaker/rust,sae-bom/rust,zachwick/rust,GBGamer/rust,ebfull/rust,aidancully/rust,aepsil0n/rust,kwantam/rust,pczarn/rust,defuz/rust,dinfuehr/rust,omasanori/rust,zubron/rust,mitsuhiko/rust,GBGamer/rust,seanrivera/rust,graydon/rust,AerialX/rust,fabricedesre/rust,emk/rust,fabricedesre/rust,ejjeong/rust,kwantam/rust,0x73/rust,dinfuehr/rust,ktossell/rust,michaelballantyne/rust-gpu,nham/rust,richo/rust,AerialX/rust,dinfuehr/rust,GBGamer/rust,jashank/rust,SiegeLord/rust,XMPPwocky/rust,defuz/rust,ebfull/rust,nwin/rust,philyoon/rust,reem/rust,gifnksm/rust,erickt/rust,philyoon/rust,cllns/rust,krzysz00/rust,pczarn/rust,j16r/rust,ruud-v-a/rust,sarojaba/rust-doc-korean,cllns/rust,bombless/rust,ejjeong/rust,jbclements/rust,XMPPwocky/rust,carols10cents/rust,andars/rust,j16r/rust,jashank/rust,zachwick/rust,l0kod/rust,jroesch/rust,AerialX/rust-rt-minimal,bombless/rust-docs-chinese,andars/rust,victorvde/rust,avdi/rust,cllns/rust,stepancheg/rust-ide-rust,LeoTestard/rust,l0kod/rust,miniupnp/rust,erickt/rust,nham/rust,KokaKiwi/rust,ejjeong/rust,rohitjoshi/rust,stepancheg/rust-ide-rust,mahkoh/rust,j16r/rust,kmcallister/rust,defuz/rust,sarojaba/rust-doc-korean,kimroen/rust,barosl/rust,andars/rust,LeoTestard/rust,miniupnp/rust,mahkoh/rust,kwantam/rust,gifnksm/rust,jashank/rust,omasanori/rust,graydon/rust,jroesch/rust,gifnksm/rust,erickt/rust