Add Span constructors for arrays and vectors
Add Span constructors for arrays and vectors

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