update core codemirror

Signed-off-by: Chris Granger <ibdknox@gmail.com>
Merge branch 'master' of github.com:Kodowa/Light-Table-Playground
fix menu for the latest nw

Signed-off-by: Chris Granger <ibdknox@gmail.com>
fix menu for the latest nw

Signed-off-by: Chris Granger <ibdknox@gmail.com>
fix the skins and themes to no longer use css variables as they've been removed in the latest versions of chromium. You can now use node-webkit 10+

Signed-off-by: Chris Granger <ibdknox@gmail.com>
Merge branch 'master' of github.com:Kodowa/Light-Table-Playground
ibdknox.css: fix tab coloring

To see what this commit does do following:
1. Set editor theme to "ibdknox".
2. In new-dark.css change var-highlight-fg to #0f0. Save new-dark.css.
3. Connect to 'Light Table UI'.
4. Open multiple editors, change content in one of them. Don't save!
5. Switch between editors, notice color changes in tab names.
6. Undo/redo the change introduced by this commit. Goto step 5.