Merge branch 'louis77:development' into development

Update Application.vala

Final hardcoded version bump

Bump to version 1.5.2

Update taglib 1.11 to 1.12

Add release info to appdata

Merge pull request louis77#64 from ryonakano/ryonakano/setup-l10n

l10n: Correctly setup the locales

Remove multiple default screenshots, fixes louis77#62

Update screenshots, prepare for 1.4.2 release

Change email address (no more FSF)

Prepare for release 1.4.0