+ Refactor code

Merged branch 'issue-87'

The problem was in precedence of ternary operator and + sign.

Merge branch 'fix-nan'

Remove parseInt(.., 10)
Move $.post(..., 'json') to $.postJSON

+ Move ajax requests to promises base
+ Define constants for API URLs
+ Handle errors based on network connections problems as well as server-side logic errors
+ Generalize code so it can be used by modules & submodules simultaneously
+ Update name of module after 1 second, not waiting for focus out event

- sql refactoring
- fix incorrect function's Сase (handler/map.php)
- fix group attaching (incorrect attaching/deattaching)
- fix incorrect sql function usage (see InternalIsMapCreated in ChangeDisciplineControl)
- fix grades without degree (sp CreateGrade), (+sql fixes file)
- add error handling for module name changing
- remove redundant console.log
- fix lost extra rates (student index page)
- improper exam rate (student index page)

Just moved id attributes to data-id.
Don't think it was such a critical issue as I thought before.

* Add typeWatcher for search form
* Replace `strlen` to `mb_strlen`, because we limit count of chars rather than count of bytes

* Fix search for students by 1-2 letters and with group filter

+ Add animation for modules swaps
+ Add always / error callbacks to $.post requests
+ Remove usages of deprecated variables & functions
+ Format code, apply naming conventions

+ Font awesome icons
+ Split js code into functions
+ Improved appearance