Added downloadable checkbox
Added `downloadable` to database and backend
Merge branch 'master' into downloadable

Conflicts:
	assets/min/main.js
Centered dialog
Version to 2.6.1
Moved code part
Build
Hide download button when downloadable is off
Added downloadable to Infobox and improved naming
Hide download photo when downloadable is disabled
Disable download php-side
Added new features to changelog
Fixed Lychee to working in IE #148
Merge branch 'master' into downloadable
Merge branch 'master' into hotfix/ie
Merge branch 'hotfix/ie' into downloadable
Added IE support to changelog
Updated browser support FAQ
Updated jQuery
Updated version