[WIP] License clarification and rewrite code samples

[parlough]

I still have to rewrite most of the code samples but I have started setting up some of the changes and clarifying licenses. People can review as I go.

In this PR I will also be updating other information as it stands in API 7.

Will address #689 when finished.

This should also close #640 and #618

[parlough]

There's a long way to go, but @ST-DDT you should have push access if you ever have a chance to lend a hand. Don't really have a list to track what I've rewritten at the moment, but you can just look at files changed for now.

[parlough]

Will need to modify the theme a little bit once this is done to add MIT to the footer - https://github.com/SpongePowered/sponge-docs-theme/blob/master/src/theme/templates/footer.html

[Inscrutable]

There is also the possibility of using the Unlicense license for the code. http://unlicense.org/

[ST-DDT]

Please resolve merge conflicts.

[Inscrutable]

@parlough what has become of thee?

[ST-DDT]

@parlough Can we merge most of this in, so that it does not gather any more dust? AFAIK everything can be merged except for the code samples license.

If you want I can give you a helping hand and fix the merge conflicts for you, then you just have to select the parts that can be merged earlier.

[Inscrutable]

I'm afraid that @parlough has been unavailable/busy IRL for the last few months, so if you can clean this up @ST-DDT it would probably be the most expedient solution.

[ST-DDT]

Superseded by #773