v1.2.0: Supports outputting PSIPRED HFORMAT

Added

• Functionality to output files with the PSIPRED HFORMAT (.horiz files) for parity with PSIPRED's H and V formats. Also allows easier future incorporation of S4PRED into the PSIPRED Workbench.
• An example of the output in example/1qys.horiz.
• Details to the README.md regarding the output format.

Changed

• Fixed version number of output ss2 file header in run_model.py.
• README.md to correct typos and improve clarity.