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)

Unimplemented:

• full file rollback (move, parent directory recovery)
• directory rollback
• refreshing on system file type changes
• different encoding support
• user labels
• extended history table in Show History dialogs

Notes:

• history is now bounded by 5 days period.