[TEST] move regexes test to ./test folder
[TEST] add Numpress test
[FEATURE] add support for ms-numpress

- ms-numpress is a library implementing several compression schemes for
  numeric data  from mass spectrometers.
  See https://github.com/ms-numpress/ms-numpress
- this commit implements support for reading mzML file that contain data
  compressed with ms-numpress. Currently the de-compression is done
  through pyOpenMS (Python bindings for OpenMS).
[DOC,TEST] add documentation

- add documentation about testing
- allow testing without invoking the ms-numpress tests
Merge pull request #17 from hroest/numpress

Numpress enabled. Thanks