Improved error reporting and added tests for it
I found that at some points I was throwing Error objects, and at others
I was throwing strings. I changed them all to strings for consistency,
and because if a string works, then why construct a useless object around
it.
Fix sjcl check, test all documented exceptions
If you check for !sjcl then that check will in itself error. Checking
whether its type is undefined does have the desired effect, though.
I took the exceptions documented in the naturaldocs comments and added
a test for each one, seeing that they are actually being thrown.