Create README.md

Add a long-overdue README with basic instructions for installing and using PlasmaTransfusion.
Create LICENSE.txt

Add missing explicit license.
Merge pull request #1 from Lunanne/GUI

Add PyQt4 GUI.
Move check for PyHSPlasma before first use of the module.

Fixes a nice little exception that would occur if PyHSPlasma could
not be found, defeating the entire purpose of catching the import.
Normalize logging settings and output formatting.