removed strstream from SharedPythonOStream

This commit includes what seems like an unrelated change in svm.cpp, but it seems that
the previous SharedPythonOStream implementation was making up for a misreported persistent_size
in the svm_parameter object.

I believe the final two string recastings of close in the SharedPythonOStream class to be the
place where the string length got adjusted, but I'm not sure exactly how that worked.

Furthermore, the SharedPythonOStream object has undergone substantial changes because it
was previously internally sharing a character buffer between a strstream and a PyString object.
Using stringstream, this is not possible, so any code relating to it is removed.
corrected getStream() declaration for SharedPythonOStream

In my previous commit, I removed the const keyword from the definition but left it
in the declaration. This is a good time to not that I'm taking the const keyword
out because the compiler errors when it tries to cast the stringstream into
a const ostream.
added proper length reference

In my big commit, I missed changing a variable to getting the size of a stringstream
directly. That is corrected here.
updated copyright years in touched files

Since it's a new year, I incremented the year for the files I'll be
proposing changes to.
fixed some style issues

Added underscores to the ends of class data members. Added a more
detailed class description.
Merge branch 'master' into remove-strstream

Conflicts:
	lang/py/support/PythonStream.cpp
	lang/py/support/PythonStream.hpp
	nta/algorithms/svm.cpp

The conflicts were in the year of the Numenta rights headers of the file. I had updated them to 2014, but I'll bring them back to 2013.

I bet all these headers will be updated together in a pull request before too long.
Merge pull request #545 from danstanton/remove-strstream

deprecate strstream, move to sstring
Merge branch 'master' of github.com:numenta/nupic