Move size limits to module-global
Move size limits to module-global

As well, this renames those variables to match PEP8 and this clears up
the comment relating to VALID_DATA_LIMIT.

Admittedly, this commit is mainly to make the following ones cleaner.

JeremyRubin/bitcoin,midnightmagic/bitcoin,Xekyo/bitcoin,qtumproject/qtum,AkioNak/bitcoin,ajtowns/bitcoin,litecoin-project/litecoin,apoelstra/bitcoin,ajtowns/bitcoin,ElementsProject/elements,bitcoinknots/bitcoin,yenliangl/bitcoin,GroestlCoin/bitcoin,qtumproject/qtum,AkioNak/bitcoin,alecalve/bitcoin,jonasschnelli/bitcoin,GroestlCoin/GroestlCoin,sstone/bitcoin,pstratem/bitcoin,bitcoin/bitcoin,anditto/bitcoin,ElementsProject/elements,qtumproject/qtum,domob1812/bitcoin,n1bor/bitcoin,GroestlCoin/GroestlCoin,fujicoin/fujicoin,practicalswift/bitcoin,jambolo/bitcoin,EthanHeilman/bitcoin,pataquets/namecoin-core,mm-s/bitcoin,MarcoFalke/bitcoin,kallewoof/bitcoin,fanquake/bitcoin,practicalswift/bitcoin,lateminer/bitcoin,fanquake/bitcoin,qtumproject/qtum,bitcoinsSG/bitcoin,pataquets/namecoin-core,lateminer/bitcoin,AkioNak/bitcoin,practicalswift/bitcoin,EthanHeilman/bitcoin,jamesob/bitcoin,mruddy/bitcoin,pataquets/namecoin-core,instagibbs/bitcoin,kallewoof/bitcoin,jonasschnelli/bitcoin,litecoin-project/litecoin,apoelstra/bitcoin,jamesob/bitcoin,namecoin/namecore,fanquake/bitcoin,ElementsProject/elements,pstratem/bitcoin,pstratem/bitcoin,n1bor/bitcoin,cdecker/bitcoin,jonasschnelli/bitcoin,alecalve/bitcoin,domob1812/namecore,jonasschnelli/bitcoin,prusnak/bitcoin,yenliangl/bitcoin,dscotese/bitcoin,jamesob/bitcoin,mruddy/bitcoin,instagibbs/bitcoin,alecalve/bitcoin,domob1812/bitcoin,domob1812/namecore,instagibbs/bitcoin,GroestlCoin/bitcoin,bitcoinknots/bitcoin,achow101/bitcoin,Sjors/bitcoin,domob1812/bitcoin,fanquake/bitcoin,fujicoin/fujicoin,ajtowns/bitcoin,litecoin-project/litecoin,bitcoinsSG/bitcoin,bitcoinknots/bitcoin,pstratem/bitcoin,EthanHeilman/bitcoin,sipsorcery/bitcoin,sipsorcery/bitcoin,MeshCollider/bitcoin,jonasschnelli/bitcoin,pstratem/bitcoin,GroestlCoin/GroestlCoin,AkioNak/bitcoin,jnewbery/bitcoin,EthanHeilman/bitcoin,Xekyo/bitcoin,sstone/bitcoin,JeremyRubin/bitcoin,tecnovert/particl-core,rnicoll/dogecoin,domob1812/bitcoin,achow101/bitcoin,Xekyo/bitcoin,qtumproject/qtum,bitcoinknots/bitcoin,MarcoFalke/bitcoin,MeshCollider/bitcoin,practicalswift/bitcoin,anditto/bitcoin,EthanHeilman/bitcoin,midnightmagic/bitcoin,apoelstra/bitcoin,Sjors/bitcoin,Sjors/bitcoin,yenliangl/bitcoin,mruddy/bitcoin,Xekyo/bitcoin,tecnovert/particl-core,GroestlCoin/GroestlCoin,particl/particl-core,domob1812/namecore,jambolo/bitcoin,jlopp/statoshi,jambolo/bitcoin,particl/particl-core,domob1812/bitcoin,mm-s/bitcoin,jlopp/statoshi,anditto/bitcoin,yenliangl/bitcoin,namecoin/namecoin-core,MarcoFalke/bitcoin,domob1812/namecore,instagibbs/bitcoin,dscotese/bitcoin,MarcoFalke/bitcoin,mm-s/bitcoin,litecoin-project/litecoin,ajtowns/bitcoin,sipsorcery/bitcoin,sstone/bitcoin,prusnak/bitcoin,bitcoinsSG/bitcoin,cdecker/bitcoin,tecnovert/particl-core,tecnovert/particl-core,MeshCollider/bitcoin,jnewbery/bitcoin,ElementsProject/elements,pataquets/namecoin-core,bitcoin/bitcoin,achow101/bitcoin,mm-s/bitcoin,alecalve/bitcoin,MarcoFalke/bitcoin,andreaskern/bitcoin,kallewoof/bitcoin,midnightmagic/bitcoin,jlopp/statoshi,MeshCollider/bitcoin,jamesob/bitcoin,mruddy/bitcoin,yenliangl/bitcoin,sipsorcery/bitcoin,namecoin/namecoin-core,fujicoin/fujicoin,ElementsProject/elements,particl/particl-core,practicalswift/bitcoin,jamesob/bitcoin,pstratem/bitcoin,achow101/bitcoin,JeremyRubin/bitcoin,sstone/bitcoin,andreaskern/bitcoin,fujicoin/fujicoin,mm-s/bitcoin,kallewoof/bitcoin,lateminer/bitcoin,fujicoin/fujicoin,jambolo/bitcoin,tecnovert/particl-core,fanquake/bitcoin,MeshCollider/bitcoin,dscotese/bitcoin,dscotese/bitcoin,Xekyo/bitcoin,GroestlCoin/bitcoin,rnicoll/dogecoin,n1bor/bitcoin,Sjors/bitcoin,pataquets/namecoin-core,prusnak/bitcoin,instagibbs/bitcoin,rnicoll/dogecoin,andreaskern/bitcoin,namecoin/namecoin-core,mm-s/bitcoin,sstone/bitcoin,anditto/bitcoin,JeremyRubin/bitcoin,pataquets/namecoin-core,namecoin/namecore,dscotese/bitcoin,n1bor/bitcoin,bitcoinknots/bitcoin,rnicoll/bitcoin,fujicoin/fujicoin,sstone/bitcoin,bitcoinsSG/bitcoin,tecnovert/particl-core,particl/particl-core,qtumproject/qtum,jnewbery/bitcoin,mruddy/bitcoin,apoelstra/bitcoin,namecoin/namecoin-core,sipsorcery/bitcoin,midnightmagic/bitcoin,andreaskern/bitcoin,anditto/bitcoin,cdecker/bitcoin,bitcoin/bitcoin,AkioNak/bitcoin,prusnak/bitcoin,andreaskern/bitcoin,GroestlCoin/GroestlCoin,namecoin/namecoin-core,andreaskern/bitcoin,domob1812/namecore,GroestlCoin/bitcoin,Xekyo/bitcoin,fanquake/bitcoin,namecoin/namecoin-core,alecalve/bitcoin,GroestlCoin/bitcoin,namecoin/namecore,cdecker/bitcoin,jnewbery/bitcoin,instagibbs/bitcoin,kallewoof/bitcoin,jlopp/statoshi,rnicoll/bitcoin,jlopp/statoshi,ElementsProject/elements,jamesob/bitcoin,jambolo/bitcoin,achow101/bitcoin,jambolo/bitcoin,rnicoll/bitcoin,MarcoFalke/bitcoin,namecoin/namecore,lateminer/bitcoin,achow101/bitcoin,domob1812/bitcoin,MeshCollider/bitcoin,n1bor/bitcoin,bitcoin/bitcoin,rnicoll/dogecoin,rnicoll/bitcoin,midnightmagic/bitcoin,prusnak/bitcoin,jnewbery/bitcoin,rnicoll/bitcoin,anditto/bitcoin,namecoin/namecore,particl/particl-core,ajtowns/bitcoin,qtumproject/qtum,lateminer/bitcoin,rnicoll/bitcoin,AkioNak/bitcoin,dscotese/bitcoin,GroestlCoin/bitcoin,bitcoinsSG/bitcoin,JeremyRubin/bitcoin,sipsorcery/bitcoin,jlopp/statoshi,Sjors/bitcoin,cdecker/bitcoin,yenliangl/bitcoin,litecoin-project/litecoin,litecoin-project/litecoin,particl/particl-core,mruddy/bitcoin,JeremyRubin/bitcoin,practicalswift/bitcoin,bitcoin/bitcoin,apoelstra/bitcoin,midnightmagic/bitcoin,cdecker/bitcoin,lateminer/bitcoin,prusnak/bitcoin,kallewoof/bitcoin,EthanHeilman/bitcoin,domob1812/namecore,n1bor/bitcoin,alecalve/bitcoin,GroestlCoin/GroestlCoin,rnicoll/dogecoin,bitcoinsSG/bitcoin,namecoin/namecore,bitcoin/bitcoin,apoelstra/bitcoin,ajtowns/bitcoin