QmlJS checks: Add check for spacing around binary operators.

Adapted from QtChecker.

Change-Id: I434582314e6431c56c9628a5a642bbfb032dfc2f
Reviewed-on: http://codereview.qt-project.org/5857


Reviewed-by: Fawzi Mohamed <fawzi.mohamed@nokia.com>
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>