Fixes #51 Open file in last active window
Fixes #48 Select Up dir + Down + siblings

Key bindings have been chosen arbitrarily to
U, D, S and s
Merge pull request #60 from syl20bnr/fixes_51

Fixes #51 Open file in last active window
Merge pull request #64 from syl20bnr/Fixes_48_go_up_down_node

Fixes #48 Select Up dir + Down + siblings
Add popwin support through around advices
rename inner functions
Add support for window selection via window-numbering

Example:
To open a node in window number 2 press: 2-RET
Merge pull request #65 from syl20bnr/popwin-support

Add popwin support through around advices
Merge pull request #66 from syl20bnr/window-numbering-support

Add support for window selection via window-numbering
When neotree-window is created, do not auto select
Fix error in docstring for neo-show-updir-line
Merge pull request #67 from syl20bnr/Fix-docstring-show-updir

Fix error in docstring for neo-show-updir-line
Fix bad indentation of files
A customizable mode-line for neotree