Add a lookahead wrapper for the token stream
Add simple first pass at parsing expressions

- only additions at the moment
Remove superfluous e when printing out scalars
Fix stupid naming bug again.

- It's probably a good idea to rename "name"
  as "tokentype"
Reorganize factor parsing to recognize coefficientless form
Fix output to remove unit coefficients
The comment lies.
Add support for negating a multivector
Add support for subtraction in the parser
Fix missing entry, when printing just 1.
Add hacky support for unary minus.

Fixes #16. Closes #1.
Merge parser to master branch