Multiarch plugins prep; relates to syncany/syncany#204
Squashed 'core/' changes from 8d7beb3..abb737c

abb737c Multiarch plugins; relates to #204
9739932 Merge pull request #246 from vwiencek/feature/prepgui
a4805ba make distinction between arch and os
306aafc add environment parameter to pluginOperation modify EnvironmentUtil to make it more consistent

git-subtree-dir: core
git-subtree-split: abb737cfaf6fe048cb8dbdd84b73a4c8aea3381a
Merge commit 'c484c0c5d9f781aee017efa0a404a5ae1baac1bb' into feature/multiarch