[javascript mode] Fix bad indentation below if

Closes #1662
Add another exception to the spanAffectsWrapping hack

And turn the hack off in recent Chrome builds.

Issue #1663
Fix removeKeyMap for string keymap values
[python mode] Add MIME for Cython dialect
Fix bug in addLineWidget.

Fixed clipping of the insertAt index.
Fix addLineWidget documentation.

Removed "pos" parameter.
Fix selecting until the start of a bidi line
Support 'title' option to markText

Issue #1654