added build description
copied tests from martijnr/XPathJS_javarosa
Revert "copied tests from martijnr/XPathJS_javarosa"

This reverts commit ff4d357de66ad7c5558a344f49d6d495c39db11f.
copied unchanged test files from martijnr/XPathJS_javarosa
swapped XPathJS_javarosa with wgxpath-java-rosa. Described how to run tests
added built file
edited build instructions