Vertical align right-aligned header text

Since e907306b411 ("Right align header text that also has right-aligned
row text"), right-aligned elements are no longer centered vertically.
This can be noticed with some Qt styles (e.g. Breeze).
searchengine: Update KickassTorrents url

Closes #2228.
Merge pull request #2229 from pmzqla/vertical-align

Vertical align right-aligned header text
Merge pull request #2230 from pmzqla/searchengine-kat

searchengine: Update KickassTorrents url
Fix compilation on ARM. Closes #2204.
Update Changelog.