Fixes version number

Updates the README significantly.

master (/): Bumps to v0.3.4 with a number of bug fixes

Changes committed:
	modified:   setup.py

master: Bumps version number for release two today.

Changes committed:
	modified:   setup.py

master (tests/): Adds affine tests to the multivariable functions.

Changes committed:
	modified:   tests/test_auto_diff_unit.py

Fixes exponentiation support in auto_diff.

Update README.md