/session/:sessionId/element/:id/enabled should return a boolean value.

Signed-off-by: Matt Isaacs <misaacs@gilt.com>
Merge pull request #852 from haveahennessy/iselement-fix

/session/:sessionId/element/:id/enabled should return a boolean value.
Updated Exception handling in scrollto for android
Merge pull request #849 from mutualmobile/android_scrollTo_support

Added scrollTo support for Android.