[BUGFIX] Test loginUser before frontendUserRepository

Prevents a PHP warning if $GLOBALS['TSFE']->fe_user->user is not set
[BUGFIX] Add form scope to class alias map
Merge pull request #599 from cedricziel/fixFormAlias

[BUGFIX] Add form scope to class alias map
[DOC] Fix small typos in comments
Merge pull request #601 from coding46/patch-1

[DOC] Fix small typos in comments
Merge pull request #580 from dogawaf/patch-2

[BUGFIX] Test loginUser before frontendUserRepository