Adds system preferences to template context

It's now possible to use
  $gimme->getSystemPreference(preferenceName, defaultValue)
in the templates. For preference names the machine names should be
used. The default value will be returned if the preferences it not
set.
Merge pull request #899 from m038/CS-5584

Adds system preferences to template context
Merge remote-tracking branch 'upstream/v4.3' into v4.3
CS-4766 Fix several issues with translation of support settings
TW-47: Fixes issue with not working getCaption method and property on images
Merge pull request #904 from m038/TW-47

TW-47: Fixes issue with not working getCaption method and property on im...
Merge pull request #906 from danielhjames/CS-4766

CS-4766 Fix several issues with translation of support settings
Add again missing author route
Merge remote-tracking branch 'upstream/v4.3' into v4.3