Reorganize last clause

Reorganize and rename the last clause. It was titled 'Amendments', but the name was inaccurate, because the content of the clause contained points not directly related to amendments. It has been renamed to 'Governing Documents', which is more accurate.

Point 11.1.1 was very ambiguous, and has been reworded. The scope of the constitution has been made more clear. An additional point was added to 11.2 to make clear the purpose and scope of the by-laws as well.