All verb paradigms now require explicit root

This was unnecessary since the root & pattern verbs are
a closed group and we have an exhaustive list of them.
Now calling mkV without a root implies you are
constructing a loan verb.
Include Irregular verb class
ResMlt.mkRoot is more forgiving (accepts anything delimited by hyphens)
Classify strong-weak-weak as Lacking (weak-final)
Remove redundant spaces before ++ in error msgs
Some missing pattern match cases (minor)
First compilable version of DictMlt

Although the following are commented out:
- irregular verbs (with ' in root)
- radicals with double consonants, e.g. k-m-pl-j