new blueprint xml compiler, add exercise colors
[dev] fix socket privileges on vagrant
update dependencies

dg/dibi 2.1.1 => 2.2.0-RC
kdyby/redis dev-master
kdyby/facebook dev-master
add petrp/access
[tests] add BlueprintCompiler test
[cs] minor
[dev] add pgsql extension to vagrant
[dev] fix failing unit tests on travis due to missing bc
fix atomicity of cache mkdir
[dev] update vagrant elasticsearch to 1.1
[squash] test if video exists