remove src_dir from .coveralls.yml

this was added to fix a bug - now we need to remove it :-)

sqlite3 tests require the ext-sqlite3 module

changed the extension on the request of @thijskh

add sqlite3 as a dev dependency. you might not notice this when running
tests locally otherwise.

Avoids:
ERROR 1170 (42000): BLOB/TEXT column 'uid' used in key specification without a key length

Minor optimalization - Don't gather settings if we don't use them

Don't gather the proxy.auth setting if we don't use it

Feature/proxy auth

This will invoke a more convenient on screen keyboard on mobile
devices and give some syntax validation as a bonus.

Try with "composer update" instead of "composer install". The latter does not support --prefer-lowest.

Since this branch is now officially released we need to support it.

* Remove 404 link to SSP news; this is covered on simplesamlphp.org now.
* Make screenshots link relative, so docs don't trigger insecure
  content warnings.
* Compress png images.

Fix/keep empty folders

Update translations to the latest changes registered in translation.rnd.feide.no. The portal is now down, so any new translations must come as pull requests.

(being respectful with occurences that might change the behaviour, i.e. default database prefixes)