Removing unreachable code that generates compilation warning.

(cherry picked from commit 89b23c4cbe881d8949e4815cf09e88111da41a36)
Fix some of compilation warnings

(cherry picked from commit 3e75521c1b8fdc4881d77b86ec9db31c2f9a8c40)

Conflicts:
	lib/preferences-dialog.vala
Update ca.po

Updated translation: added missing strings and improved translation of existing ones.

(cherry picked from commit 1fa0e7a25494ecc0124ebbfa647bbe4be76b311b)