WIP. Attempting to add .xlsx functionality, but it is proving much more difficult than expected
Added Excel functionality. outputs as .xml. Will not be portable as there are .dlls for this version
fixed v1.0.1 to be portable so long as .dlls are in the same folder.
merging to master, final check in
Managed to repack for a fully portable version
Merge pull request #2 from menglmaier/v1.0.1

V1.0.1