Add searchtasks plugin.
SearchTasks, Powerline, Python, cleanup, NERDTreeToggleCWD()

Changes:
- added SearchTasks plugin
- re-apply indent for python files; something turns it off
- Added generic python run keybind
- Removed *.txt from autocmd textfile formating. It turned spelling on for
  help files; very annoying.
- decrease insert mode exit/enter delay
- Powerline custom config support
- minor layout refactoring
- NERDTreeToggleCWD()
Submodule: Update powerline