Remove HTML module

If you want to do stuff with HTML, do it yourself.

touch #19
Move some dependencies to `test_requires`

touch #19
Minor typo in setup.py
Remove spam module

Tests were already commented out, spambayes project is pretty much dead.

touch #19
Skip failing test

It's not actually testing for something we want, but could be the basis
of a future test.
Merge branch '19-reduce-dependencies' into salmon-next

Closes #19