Richer String Literal Support

Currently, string tokenizing is pretty boring. No escape sequences or anything. It's just: quotation mark, some text, quotation mark.

Definitely want to support escape sequences: The standard C ones, literals (\", \', etc.), possibly a generalized Unicode one (\uNNNN, for instance)
Disallow newlines unless explicitly requested with a backslash before the newline
Raw string syntax which ignores all of the above and allows newlines freely.

Mercerenies / tfactor