[BUGFIX] Test loginUser before frontendUserRepository

Prevents a PHP warning if $GLOBALS['TSFE']->fe_user->user is not set
[BUGFIX] Wrong condition for checking Url

to check if the site URL is not already the first part
the condition should be 0 !== strpos....
Merge pull request #598 from michaelstaatz/development

[BUGFIX] Wrong condition for checking Url
[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
Merge remote-tracking branch 'upstream/development' into workbench/namespaces