Added some basic hypergraph utility methods.
pep8 compliance
Split superClass HyperGraph into two files
New sub classes
Created read hypergraphs tests
Implemented write directed and undirected graphs to file
added tests for both methods.
readDirectedHypergraph/writeDirectedHypergraph functions are renamed to be simply read/write
Fix pep8 compatability
Merge pull request #9 from tmmurali/splitSuperClass

Split super class