Merge pull request #7 from potfur/dev

mostly - added pgsql support
fixed phpdoc
refactored (plenty)
extracted from duplication having/where
removed builder alias
scrutenizer/travis configs
fixed return value
field wasn't passed by reference
refactored join
Merge pull request #8 from potfur/dev

Dev
Merge pull request #9 from potfur/dev

Dev
readme