Merge pull request #163 from sn6uv/docs06

Mathics 0.6 documentation
fix typo in from_sympy
basic unittesting
run unittests with setup.py test
add basic selenium frontend tests
tidy test_frontend.py
add parser unittests
add simple console unittests
replace unittest with unittest2
only import unittest2 for python2.6
more web frontend tests
setup xvfb during travis tests for selenium and initialize mathics server database
add setup.py test command
remove sleep from frontend tests
sympy.Real -> sympy.Float
initialize mathics server once for test_frontend
test_frontend graceful failure
attempt to fix test_frontend race conditions