Simpler Constructor for CrossingIndex

You can directly pass the segment parameters to the constructor.
Reorganized Readers

Added marker interface for all readers.
Utilizing Constraint Type

Evaluating constraint type as reported in log file
instead of counting the number of paths.
Directed Graph
PathValidator Edges
Edge as Source-Target Tuple instead of ID
Simplified GraphReader Tests
ResourceBasedTest Constructor
Simplified BranchCoverage Tests
Created PathReader

PathReader instead of PathValidator since we need the path information in
more than one place. Accounts for crossings as endpoints of a path.
ConstraintValidator Refactored

Rewrote tests to keep it DRY. ConstraintValidator allows crossings
as nodes of a Kuratowski subdivision.
Refactored PathReaderTest
Main Program

MainValidator and executable class. Adapted BranchCoverageValidator to respect log output notation.
Added Remaining Documentation
Tests for MainValidator

Added test for valid log files. Invalid log file examples are still missing.
Merge pull request #2 from TiloW/MainValidator

Main validator