Fixes to the way Render handles attributes

[theashguy]

Prior to this PR Render could only handle attributes without any punctuation in them OR hyphenated attributes. There are however a range of weird and wonderful attributes inside SVG and that various Javascript libraries use that require other types of punctuation OR multiple instances of punctuation in an attribute.

This PR improves the state of this (though I believe there are still some holes in how it works-- eg, I'm not sure it works if attributes begin with punctuation).

Additionally, it opens up the ability for attribute content to have special characters in it-- a requirement if you want to pre-load some data into a JS script for instance as a json object.

[theashguy]

Have added my notes for review. @Schniz @vpzomtrrfrt @Tarnadas