Improves multilingual form

* Fixes typo in English language item
* Adds missing object property documentation
* Removes necessary object property
* Disables unsetting default language as available language since it will be added anyway again
Use proper UTF-8 MINUS SIGN
Removed hgroup tag
Merge branch 'master' of github.com:WoltLab/WCF
Uses class constant instead of magic number
Prevents erroneous cronjobs form causing repeated cache reset

Fixes #1194
Fixes cronjob issues

Closes #1185
Closes #1197
Added missing language variables
Merge branch 'master' of github.com:WoltLab/WCF
User Panel dropdowns are now always active

Hint: doubleclick bypasses the dropdown
Merge branch 'master' of github.com:WoltLab/WCF
Updates cronjob fail counter during manual cronjob execution

…and disables failed cronjob if it failed too often
Merge branch 'master' of github.com:WoltLab/WCF
Fixes bug when reopening cronjob log error message

They could only be opened once and when reopening them, nothing happened since the DOM element had been removed.
Updating badge on user panel loaded
Fixed small style issues
Merge pull request #1252 from WoltLab/minusSign

Hyphen vs Minus
Fixed future timestamps
Merge branch 'master' of github.com:WoltLab/WCF
Small optimizations