Better autodetection of Soft Tabs.

Check for the presence of a space, instead of the absence of a tab.
This ensures that Soft Tabs will not be activated on a file that (for
example) starts with a BOM or something, but is otherwise full of hard
tabs.
Support built-in context menu items
Add cut/copy/paste built-in context menu items
merge latest upstream master
updated regex in usesSoftTabs to only look for Tab and Space
Added linux open-folder keybind.
Moved application:open-dev to `ctrl-alt-o`
:lipstick: simplify assignment using coffeescript magic
Add undo, redo, delete and select all commands to context menu
Upgrade find and replace to remove deprecation
Upgrade atom-dark-ui
Merge pull request #3394 from atom/iz-builtin-context-menu-commands

Add cut/copy/paste built-in context menu items
Split cursor methods into essential and extended
Buffer before screen, get before set
Deprecate getCursorScreenRow

It’s out of place, and unnecessary.
Move adding cursor functions under more heavily used functions
Remove `Cursor` from `::moveCursor*` methods
Add missing docs
Move less used function down in the order
Add methods to be symmetrical with selections

* getCursorsOrderedByBufferPosition
* getCursorBufferPositions
* getCursorScreenPositions
Deprecate methods on cursor