Update pl.yml for ContentController.StartEditing

For over a year, here is an error, resulting in the display of the broken link to the Polish version of CMS, after installation.
Merge pull request #1096 from gander/3.1

Update pl.yml for ContentController.StartEditing
MINOR: Fixed copyright year
Recompiled CSS with compass 1.0

Minor syntactical changes, like alphabetical ordering of filters, uppercasing of hex colours. See http://compass-style.org/blog/2014/08/15/omg-compass-1-0/.
Shouldn't include any user-visible changes, but helps to avoid confusion with the next person trying to modify the CSS (Luke is currently struggling with that)
Fixed duplicate CSS scoping in AssetAdmin.scss
FIX Broken links on dependent pages tab
Merge pull request #1119 from micmania1/fix-broken-links-dependent-pages

FIX Broken links on dependent pages tab
BUG sprintf missing on exception in SilverStripeNavigator
Merge pull request #1127 from halkyon/sprintf_missing

BUG sprintf missing on exception in SilverStripeNavigator