Add an UniformInterfaceException hamcrest Matcher

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Add a base interface for clients accessing a siesta endpoint

This will trigger known error/validation error filters

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Since JS/resources mentioned here are in JAR, this is unusable
Merge remote-tracking branch 'origin/master' into nexus-5790-new-content-impl