Default Path/File Mode

[bleshik]

I want to have a way to open CtrlP always in same mode. The problem is that once you toggled it using C-D, the next time you open CtrlP, it will have the last used mode.
There is g:ctrlp_by_filename option, but this one is used only first time. Maybe we can just use the option g:ctrlp_by_filename on every invocation of the Open function?

[bleshik]

Like this #279