performance
file encoding fixes: one change file encoding action instead of two (reload/save)
undo/redo change encoding
persistent fs fixes:
- fixed multiple instances of JarRoot exception with the same id
- fixed multiple instances of the root which differ in the case only
- removed clearing id cache in tests since it may lead to multiplication of same-id instances
- VirtualFile.findChildByName() performance
mac implementation of custom protocol handlers IDEA-65879
Completion Tester
Meaningful logging
Fix compilation
[git][hg] IDEA-101135 Install hg widget to the same place as in Git

Move installation to and removal from the status bar to a common utility
class, reuse both in Git and Hg.