Improve English
Merge pull request #393 from lem9/master

Improve English
Translated using Weblate (French)

Currently translated at 99.4% (948 of 954)
Merge remote-tracking branch 'origin/master'
Update po files
Configurable source language

Source language can now be set sitewide in SOURCE_LANGUAGE setting.
Closes #390
Drop not needed local variable
Translated using Weblate (Czech)

Currently translated at 100.0% (954 of 954)
Include link to complete docs in FAQ
Add script to generate secret key
Translated using Weblate (Danish)

Currently translated at 99.6% (950 of 954)
Merge remote-tracking branch 'origin/master'
Translated using Weblate (Greek)

Currently translated at 100.0% (954 of 954)
Translated using Weblate (Polish)

Currently translated at 73.9% (705 of 954)
Merge branch 'master' of https://github.com/ruleant/weblate
Merge branch 'master' of github.com:nijel/weblate
Translated using Weblate (German)

Currently translated at 65.8% (628 of 954)
Translated using Weblate (Italian)

Currently translated at 2.7% (26 of 954)
Translated using Weblate (Polish)

Currently translated at 73.9% (705 of 954)
Translated using Weblate (Portuguese (Brazil))

Currently translated at 99.8% (952 of 954)