fixes for trl link intern

- correctly link to visible page in trl which is invisible in master
- add various tests
- add test for clear cache when changing visiblity of trl page (still incomplete)
refactor link intern events internal method
correctly clear cache for trl link intern when showing/hiding page
add another test, passes
clear cache for intern link when url changes
implement other recursive events as in master
clear cache for space trl component
Add ContentSender_Download

To be used by Pdf-Component and coming DownloadAll-Component for Gallery
Add possibility to download all picture of a gallery

Not activated by default
Revert "Add ContentSender_Download"

This reverts commit ce50e446867d88191cd03774a2890700c4363b2f.
Revert "Add possibility to download all picture of a gallery"

This reverts commit 37d7c089935105fb7e0c95f67a7d23f94105eae3.
show newsletter category in controller
increase memory limit
correclty call tidyHtml when adopting text

fixes #18