new metadatagen and other - closes #56

1. new metadatagenerator library
  - average speedup (without caching) by around 60%
  - not repeating namespaces declarations - result is cleaner
  - some improvement with sql request (however it looks like more small selects have better perfomance than big joins) - closes #56
2. attribute requirements forms are no also in entityedit form (for SP)
3. SP registration form also parses md:RequestedAttribute and populates into form (only attrs which are defined in the system - AttributeDefitions)
4. code cleaning

!important!
For now the new metadatagenerator is not enabled as default
To activate it you need to set below line in config_rr.php file
$config['useNewMetagenerator'] = true;

to recognize if your system generates federation metadata in old or new way 
in new way there is a comment line on top:
nMetadata was generated on: {DATETIME} UTC