lang and format is not mandatory parameters

for good working you dont have to set these parameters
comments improved, type of variables

added variable type logger and loopinterface, logwriter is not attached
and stored to object, why to store logwriter to phpari object?
added comments, type of variables in phpari
Merge pull request #26 from matak/master

Some fields were set as mandatory while they were optional (@matak)
Some additional comments to make some of the variables in the class more readable (@matak)