readme: Remove trailing spaces.
readme: Fix the object example.
check for error existence and abort, rather than error non-existence and continue
moved parse_test to make room for a more fundamental parse_test
fixed OptionalTerm, added test for it
forgot to add test
row, col in tokens
token info put into error, tests
add rule names to errors

This can almost certainly be done better, but this is the easiest
solution I could see.