New Local History implementation

New and old Local History now work simultaneously. Therefore IDEA will consume a bit more memory than usual.
You can access new LH dialog with Show History (New)... action.

Implemented features so far:

• tracking most file changes
• showing file and directory history and difference
• basic file rollback (rename, content change)
• refreshing on file types changes

Unimplemented:

• full file rollback (move, parent directory recovery)
• directory rollback
• user labels
• extended history table in Show History dialogs

Notes:

• history is now bounded by 5 days period.
• some problems may occur with file encodings

Background VCS Operations

The following VCS operations can now be performed in the background:

• Perforce add, remove, edit and integrate
• CVS add and remove

Also, Perforce changelist synchronization no longer blocks the UI thread.