rulus.ui.core: fixed show and hide
rulus.css.core: changed getCSS to return values for one given class
rulus.ajax: first cache, then parse result
rulus.json / rulus.xml: disabled error log, itreturns undefined if there
was an error
rulus.ui.show: use "block" as default display state
Merge remote-tracking branch 'origin/master' into rulus.require