Reading .mdp files implemented
Report coverage to setup.py test
Add test for setting option in MdpFile

Fixed setting any value as str() when calling set_option.
Test added for MdpFile.remove_option
Add test for searching and printing
Merge branch 'working' into read-mdp

Conflicts:
	pygromacs/gmxfiles.py
Test added for MdpFile.save

It's a long test, which tries saving to same path (overwriting the
current file, later restoring it), removing and changing random keys
and verifying that they're saved properly, and finally verifies that
saving with a custom extension works.
Added more tests in MdpFile for non-existent parameters
Update documentation for MdpFile features
MdpOption comments no longer begin with ';'
Add extension completion for reading MdpFile's

Tries to read file at given path if it exists, else adds '.mdp'
extension if not present and tries again.
New pygromacs.utils module for verify_path

Unit tests added for function.
Add documentation for pygromacs.utils