Avoid NPE when Protodomain couldn't be created.
Protodomain can now work with SCOP domains, whole chains, and whole PDB
files instead of just SCOP domains. Other types could be added as well.
Also made other small changes.
Fixed colorBySymmetry for helices, do not report global
pseudostoichiometry results for asymmetric structures, added
QuatSymmetryScore class with various RMSD and TM scores.
Merge pull request #25 from pwrose/master

Fixed colorBySymmetry for helices, do not report global
latest version includes some fixes for helical proteins