Cleanup MontyResource and inheriting classes
Implement method MontyResource.isDirectory()

This way we can pass arround a MontyResource and determine is this is a
directory (and therefor a module/package) or a single file.
Implement MontyInputStream as InputStream-abstraction

This lets us use an InputStream (like System.in) as a MontyResource.
Remove deprecated ContextTest
Remove deprecated param -k from integrationtests
Implement CodeWriter as future baseclass for CodeContext

This class writes the generated LLVM-code to an internal StringBuffer and
allows more convenient code-generation.
Use CodeWriter as a baseclass for CodeContext
Implement new codegen classes in GCV and ContextUtils
Cleanup and PackageBuilder (unify usage of MontyResource)
Add argparse4j to pom.xml
Implement argparse4j argument-parsing in Main
Remove old codegen support classes
Remove old Params class
Merge pull request #5 from lummax/parameter_restructuring

Parameter restructuring
Set type of StringLiteral in ResolveVisitor
Implement String as corelib class
Implement (un)boxing of Strings
Test cases for String-constructor
Test cases for String as Object