Set menu drawer to overlay, inside actionbar

Instead of moving the whole screen, overlay the menudrawer on top of the
content, and inside the actionbar space.  Keeps things consistent with how
Android now does menu drawer.
Fix crash on deleting image
Remove artificial character limit on step line

This was causing problems when a step line was longer than 350 characters due
to wiki text links, the edit text field would truncate the text to 350 which is
a bad call.  We shouldn't be doing any limiting client side, instead we should
just handle the validation error the api comes back with.
Handle index field in api error responses

We added an index field to api error responses for validation errors in order
to know which field failed validation so we can direct the user to that field.