[PATCH 139/153] Port existing uses of ivy to Bootstrapper / Ivy
[PATCH 139/153] Port existing uses of ivy to Bootstrapper / Ivy

Add support for bootstrapping from an ivy.xml insted of just an ivy version to
support ivysettings plugins - the ivy svn resolver used inside Twitter drove
this.  Also add support for injecting ivysettings into all bootstrapped ivy
commands.

Fixup SubprocessExecutor.spawn to scrub its args.

RB_ID=228151

(sapling split of 8d2a425af40957cbfa8185e47b3e6613392a2abe)

cevaris/commons,WCCCEDU/twitter-commons,WCCCEDU/twitter-commons,ericzundel/commons,pombredanne/commons,VaybhavSharma/commons,VaybhavSharma/commons,atollena/commons,WCCCEDU/twitter-commons,Yasumoto/commons,nkhuyu/commons,abel-von/commons,WCCCEDU/twitter-commons,WCCCEDU/twitter-commons,cevaris/commons,VaybhavSharma/commons,brutkin/commons,atollena/commons,nkhuyu/commons,brutkin/commons,ericzundel/commons,VaybhavSharma/commons,jsirois/commons,jsirois/commons,nkhuyu/commons,ericzundel/commons,abel-von/commons,atollena/commons,pombredanne/commons,cevaris/commons,jsirois/commons,nkhuyu/commons,Yasumoto/commons,VaybhavSharma/commons,brutkin/commons,atollena/commons,abel-von/commons,brutkin/commons,pombredanne/commons,jsirois/commons,cevaris/commons,ericzundel/commons,Yasumoto/commons,pombredanne/commons,cevaris/commons,Yasumoto/commons,abel-von/commons,jsirois/commons,ericzundel/commons,nkhuyu/commons,atollena/commons,abel-von/commons,pombredanne/commons,Yasumoto/commons,brutkin/commons