Keymap to move caret to the end/start of the current line

To simply move the caret to the end/start of the current line instead of
using the `end` and `pos` keys a new mapping should be added for Linux
based OS.

- Move to the end of the current line: `Ctrl` (super) + `alt` + `→`
- Move to the start of the current line: `Ctrl` (super) + `alt` + `←`

The default mappings `⌘` + `⌥` + `←` / `→` for macOS are already
provided by default.

Closes GH-167

snowblocks/atom/keymap.cson

@@ -15,5 +15,8 @@
  # Simple and fast project management workflow.
  "ctrl-alt-p": "project-folder:add"
 
-"atom-text-editor":
+".platform-linux atom-text-editor":
  "ctrl-alt-c": "color-picker:open"
+ # Easy mappings to move the caret to the end/start of the current line instead of using "end" and "pos" keys.
+ "cmd-alt-right": "editor:move-to-end-of-screen-line"
+ "cmd-alt-left": "editor:move-to-first-character-of-line"