Mostly just implicit declarations cleanup

removed an extraneous comma on the groups tree stuff which was an error
Start fixing https://hackerone.com/reports/32529
Let's be sure that t functions receive strings
PSR-2
Remove authentication type on package removal
move content block link abstraction out into a core helper class. See issue #242
Fix package attribute key update.
Merge branch 'develop' into Fix_package_attribute_update
fixes package block composer views

re: https://github.com/concrete5/concrete5-5.7.0/issues/1426
fix empty areaToModify variable if block is added to a global area
Typo
Merge pull request #1421 from mlocati/fix-t-without-strings

Fix t without strings
adding title to rich text editor page
Display attribute placeholder text on stack page

If you add an attribute block to a stack it will render as an empty block. I adjusted to code so it behaves like it does when displaying an attribute block on a page defaults page: it shows a placeholder text.
Merge pull request #1436 from infostreams/patch-9

Typo
Fix H6 text-transform style

H6 was receiving the text-transform style set for H5
adding inspect page back in
Merge branch 'develop' of github.com:concrete5/concrete5-5.7.0 into develop
Merge pull request #1439 from jordif/patch-1

Fix H6 text-transform style (Elemental theme)
tweaks to migration