Fixed logdet distance and added paralinear. Contributed by Ben Kaehler.

[CHANGED] also turned back on a bunch of tests I had iadvertently inactivated
    some time ago.

Thanks for the fix Ben!
have gamma return a float when x=2
Merge pull request #41 from wasade/gamma_return_type

have gamma return a float when x=2
can now use PyCogent within the IPython notebook

[FIXED] trap stream IOErrors that arise in IPython notebook

--HG--
extra : rebase_source : 66b156b11ab8678306047dced17b06245baee7cf
A small bugfix enabling half-bounded optimisation to work as intended.
[FIXED] In cogent.optimisers, an upper or lower bound of None is now
    intepreted correctly, eg: bounds=(1,None) is (1,inf), not (1,-inf).
Merge branch 'master' of https://github.com/pm67nz/pycogent