Fixed usage description.
Added the ability to specify input files as '-', in order to read from STDIN.
Merge branch 'command-line-args' into develop
Added test script.
Re-worked some constructors.
Removed some unused static factory methods.
Re-worked SimpleNode and CharClass.
Tweaked test script.
Removed factory methods from SimpleNode.
Re-worked SimpleNode creation.
Removed GrammarElement et al.
Renamed DefinitionNode to Definition.
Renamed SimpleDefinitionNode to SimpleDefinition.
Extracted an overload of the Process method.
Added the BuildDefinitions2 method to automatically convert SimpleDefinition to Definition.
Switched definition type.
Removed unused methods.
Renamed method.
Removed the unused SpannerBuilder class.
Removed unused overload.