Merge pull request #83 from dmyersturnbull/master

Changes to SCOP- and CATH-related code.
updating validation file parsing
uncommenting SCOP 2 tests for now, until fixed
re-enabling test since server has been updated
Committed StructureIdentifier as a first step in issue #81.
Merge branch 'master' of https://github.com/biojava/biojava
Added some static utilities and constructors to ResidueRange.
Continuing to work on #81, changed StructureIdentifier.getString() to
StructureIdentifier.getIdentifier(), and made ScopDomain and Structure
implement StructureIdentifier.
Working on issue #81, created Substructure and UriIdentifier as two
Identifier implementations, and created the utility class Identifier.