Implements multiple selections clipboard paste

Includes:

  - Passing the selection index in the `Editor::mutateSelectedText`
method callback
  - Storing all the selections content on many calls of
`Selection::copy` with `maintainClipboard = true` in a metadata
`selections` array
  - Handling clipboard with a `selections` metadata in
the`Editor::pasteText` method
:lipstick: Fix typo in pasteText method comments
Allow newer version of `nodejs`
Adds specs for multi selections clipboard handling
+FreeBSD, -bullshit

Signed-off-by: Cthulhux <zeug@tuxproject.de>
:lipstick: Replace have with has in spec description
:lipstick: Harmonize lineForRow calls in specs
:lipstick: Use skinny arrow instead
:sweat_smile: Forgot to remove the test focus
:lipstick: Clear object deconstruction in Selection::copy
Replacing string comparison with actual int comparison
Allowing node > 1.0 (no reason not to already do that, I guess)
Add more sublime parity keybindings
Add troubleshooting to Windows build instructions
Add `fullscreen` class to body when in full screen

Add a `fullscreen` class to body when full screen is triggered, as suggested
by @orderedlist in #1694
FreeBSD

Signed-off-by: Cthulhux <zeug@tuxproject.de>
:confused: Forgot to replace most references to clipboardMetadata

Never attempt to fix a PR right before going to sleep!
:memo: Add troubleshoot document libudev in Ubuntu 14.04
Upgrade to feedback@0.33.0
Upgrade to apm@0.52.0