Handle textInput events in EditorComponent instead of on InputComponent

This commit also changes input handling to be more like it was in the
previous editor. We're using textInput rather than input events because
they are emitted *before* characters are inserted, enabling much simpler
detection of characters inserted via the accented-character menu on
OS X.

Previously I avoided this because something about it was causing reflows
in the old editor, but in this editor that doesn't seem to be a problem,
and it's actually faster.
Don't call preventDefault for spaces to prevent browser scrolling
Upgrade to markdown-preview@0.79
Upgrade to language-ruby@0.28.0
Upgrade to tree-view@0.101
Handle mousedown events only for left button in editors
Update markdown-preview@0.80
Upgrade to settings-view@0.122
Delete fixtures for force re-checkout
Remove fixtures cleaning
Upgrade to settings-view@0.123
Fail on windows if specs fail
Upgrade to settings-view@0.124
Upgrade to setings-view@0.125
Upgrade to settings-view@0.126
Merge pull request #2626 from atom/iz-mousedown-events-on-left-click-only

Handle mousedown events only for left button in editors
Upgrade to language-ruby@0.29
Merge pull request #2627 from atom/ks-windows-package-failures-on-ci

Fix packages specs on Windows CI
Ignore plist tests/
Ignore build/Release/obj directory