HgBranches feature  first take  (git-style )

* New "Branches" action for HG  invokes HgBranchPopup. So does the click on HgBranchWidget on status bar.
* HgBranchPopup shows common actions ("New branch") and the list of repositories and not active branches.
* Merge and UpdateTo branch actions are supported from PopUp view.
* HgRepository stores information about branches
* HgRepositoryReader  collects information from files
* HgRepositoryUpdater call repositpry reader if .hg files were changed externally
* Checkbox for new branch creation push added
* Check if .hg internal files exist added
* Additional checks for new repository(without any commit) added (cache,branch and other files maybe not exist)
EA-46161 - IAE: TypeConversionUtil.getClassSubstitutor