Merge pull request #375 from igorko/master

Add button_plus to minicore
New translation Scottish Gaelic (gd, Gàidhlig)
One translation fix for gd + some unnecessary reformatting thanks to differences between Virtaal & Poedit
New translation for Scottish Gaelic (gd, Gàidhlig)
Translation fix gd
Merge pull request #376 from gunchleoc/master

New translation Scottish Gaelic (gd, Gàidhlig)
Fix noalpha Shield power threshold
Clean up minicore loot images
Update animation names in minicore
Heroic Strike and Greater Channel as power upgrades
Remove test cutscene
Remove obsolete cutscene file
Default mod language updates for v0.19
Merge pull request #377 from dorkster/anim_img

Clean up some images and animations
Remove release notes from repo
Add credits and release notes
Remove unnecessary duplicate language file
Instead it should use the default mod's language list
Map layouts Salted Field and unnamed tomb
Map testing for Empyrean campaign
Updated the Galician (gl) translation