Qpformat

- feat: extract meta data from QPSeries/QPImage data files

- fix: single_tif_phaiscs (SID4Bio) contains two phase images, the second
of which is recorded at a different time point than the intensity
image. The first image is recorded in wavelengths and not in
nanometers and thus is converted using phasics metadata first.
If this metadata is not available, the second image is used.

- fix: qpimage file formats: override identifiers (clean solution)
- fix: add check for valid meta_data keys
- docs: document attributes of SeriesData

- fix: qpimage file formats: identifiers were not unique, but simply
copied from the input hdf5 file

- setup: add qpimage version dependency

- ci: automate PyPI release with travis-ci