Merge pull request #329 from GalSim-developers/#297

#297 - Storing 2D correlation functions and generating noise with these correlations
updated README to include information about the new GalSim mailing list
updated readme to reflect new correlated noise capabilities
added GNU public license v3
added the GalSim GPL statment for copy pasting into the headers of all source files
renamed license file to generic LICENSE
added GPL copyright statement to all Python source files
added GPL license to all cpp include files
modified statement in PSFCorr.h to refer to LICENSE
ditto for the .cpp src file
added GPL copyright statement to all .cpp files
added GPL copyright statement to all pysrc files
added GPL statement to the config parsers
added GPL notice to all non-json files in the examples directory: the json files are a bit of a pain, and it is not *required* to add the copyright statement to all files, but recommended
added GPL statement to everything relevant in tests
added GPL statmement to some more random odds and sods in docs, and to SConstruct
added GPL copyright info to a lot of the content in devel
Merge branch 'master' into #238