FIX mongoDriver to work with 2.6

- fixed handling of $unset property to be compatible with mongodb 2.6
Mongodb test empty unset collection
Security schemas
Security role list

Working sample.
Comparison oprators repaired
Vylistovanie Roly [Finished #71381946]
Schema editor fixed (index2.html)
[finished #71384326]
FIX TravisCI build failure

SecurityController test moved from unit to integration tests
as it depends on mongoDB.
Form layout

- add first version of form layout
- sass _variables.sccs - fix font sizes, colors
- add custom bootstrap
- add placeholder mixin
Inserted logo

-Inserted logo.
-Changed html - inserted <img> tag.
Added buttons in contenteditable.

-Added buttons:left, right, justify, h1, h2, h3, remove heading, undo,
redo
-Changed psui.css to fix problems with line height in h1, h2 and h3