cleanup for buffalo v1, added some test cases for #82 and #106

[sio4]

There were 14 open issues in this project and I reviewed most of them. Some issues are just answered, but some need additional attention further. Here, are some notes on the result of the review:

• https://github.com/gobuffalo/plush/issues/79 is somewhat tricky, but I think keeping the current behavior is just fine
• https://github.com/gobuffalo/plush/issues/82 is actually working as intended, but documenting the behavior could be better (added test case for this behavior)
• https://github.com/gobuffalo/plush/issues/106 it seems like we didn't update the documentation after changing the behavior. it should be reviewed again and need to update the documentation
• https://github.com/gobuffalo/plush/issues/99 is an issue about security and escaping. it could be worth taking a look at this issue again soon. (this issue is also related to the other partial related issues)
• It could be worth taking a look at this issue too: https://github.com/gobuffalo/plush/issues/19