New Feature: Added custom delimiter in Post.

Now while creating page/blog user can set the teaser by entering "<!--break-->"
any part of body and teaser will be created until that point. very useful to
 split the body and teaser, if no delimiter is specefied the teaser will split at 105 words.
Merge pull request #236 from sergeyklay/master

Fixes
Fixed issue: Some admin/menu controler fixes
Updated feature: Made messages when managing menu more readable