[Bugfix] Bugs #222 & #122.

Details:
1. Bug #222. Authoring: Create timeline is not working on click of enter. 
__Code review:__ http://mrccodereview.cloudapp.net/ui#review:id=1217
2. Bug #122. Authoring: Timelime: Title doesnt have max length. 
__Code review:__ http://mrccodereview.cloudapp.net/ui#review:id=1216

Notes about bug #122:
I've applied max length for title of timeline, exhibit and content item, and for attribution, media source, media url of content items on client-side. I set temp values of maxlength equal to 200 symbols. We need to specify those values for each of those fields and apply  those bounds in database also.