Removed backticks which were causing PostgreSQL installations to crash
Merge pull request #1354 from victorelu/master

Removed backticks which were causing PostgreSQL installations to crash
Czech translation

all string translated
Merge pull request #1356 from lexislav/master

Czech translation
Optimized usage of composer on travis.

There is a preinstalled version of composer on travis-ci, so we should use it.
But still keeping the `self-update`, but making it failsafe with `|| true`, if getcomposer.org might be down.
Merge pull request #1359 from h4cc/patch-1

Optimized usage of composer on travis.