Split core functionality and Maven plugin in 2 submodules

Also make the core OSGi compatible
Multi-module POM + version updates
Add format-xspec-summary.xsl

to generate an index.html aggregating all the test results into one summary
Convenience method to method find and run all tests in a specified directory
Merge pull request #7 from daisy-consoritum/osgi

Close #4. Close #7.