Boot priority support:

- list links as priority dict
- save and remove right links
Fixes for priority:

 - Fix init.d service stop,
 - Fix remove prio from link name,
 - Use more digits for priority
Fix priorities order
Add ** mark for help
Fix drop default priority, add some messages
Return missing request data
Fix form data check for autostart+priority
Fix type conversion
Remove useless field
Merge pull request #20 from sergey-dryabzhinsky/autostart-priority

Autostart priority