Initial Maven setup.

* compilation via maven.
* unit testing currently disabled from maven; needs restructuring.
* empty plugin localisation file.
Support automatic unit testing via Maven.

* Tests where moved to separate source folder (layout does still not conform to maven guidelines).
* Removed (again) JUnit plug-in dependency in manifest file.
Removed now unnecessary exclusion.

The exclusions are not necessary any more because the benchmarks and tests were moved from the 'src' to the 'test' folder.
Adding required line break at the end of the file.
Including non-Java resources from source folder.

This is necessary because the project doesn't follow the Maven folder structure.
Removing build artefacts because they should not appear in source folders.
Several minor changes to the type checking code
Merge branch 'master' of github.com:cwi-swat/rascal
fixed direct use of fast ValueFactory to prevent future wtf's.
Merge branch 'master' of github.com:cwi-swat/rascal
Merge branch 'master' of github.com:cwi-swat/rascal
Fixed issue with missing image.
a lot of changes towards implementing partially ordered values
Fixes a number of problems with datetime values
Merge branch 'master' of github.com:cwi-swat/rascal
Merge branch 'master' of git@github.com:cwi-swat/rascal.git
bumped
Fixed two problems in the JDBC library, apparently caused by changes in other parts of Rascal
Removed ability to generate negative years in the random generated datetime values since we do not currently support them
CSV writer now properly quotes string fields.

A string field that contains the field separator (e.g. comma,
semi-colon, etc) is now properly quoted string on writing.