calc_avg and calc_sigma had some errors, apologies

 - added more stuff for dictionary type behaviour
 - added save functionality (Thanks Ryoichi!)
in plt class:
 - more goodies added

(calculates averages instead of printing all)

(to generate a combined partran.out from studies

better skip function (hopefully)

this is VERY buggy,
as there are some data written to file which are
NOT DOCUMENTED

fix for python 2.6 (SLC6)