Squashed 'src/JS-Algebra/' changes from 9bb4d48..ea2ad4c

ea2ad4c Merge branch 'master' of https://github.com/MatthewJA/JS-Algebra
d9b9412 Added toString method for AlgebraException, so that when it occurs you actually see something useful.
e2098ff Removed snarkiness from README, as there is now code.
e860895 More tests, which are less terrible.
307fe07 Minor .gitignore change.

git-subtree-dir: src/JS-Algebra
git-subtree-split: ea2ad4c6dba1b0d53c1001279a6f04735fd0b89e
Merge commit '9c889f6c65b52eaa00b45cb4e43081a7f83f8adc'