Pbxplore

- Add and update version number in zenodo config file
- Update authors affiliations in README
- Fix typo in documentation
- Add example of RMSD and Neq in documentation

- Update test engine from nose to pytest
- Add metadata for Zenodo integration

- Add a version option for scripts (based on pbxplore.__version__)
- update doc for installation and configuration
- Fix weblogo compatibility
- Update conda procedure
- Update authors list in documentation

- Update documentation
- Notebooks doc are now Python3
- Use nbsphinx for notebooks conversion

- Remove demonstration scripts
- Fix encoding issue with weblogo file (152)
- Move print statement of PDBs read from PDB class to the loader module
- add a property in PDB class to get the number of chains
- add a progress bar during PB assignment of a trajectory (150)
- fix visualization functions when the index of first residue is different of 1 (148)
- update documentation
- update example files for documentation (and related doc)
- update Travis with Python 3.6
- PBxplore is now fully compliant with Python 3.6

- update RELEASE doc (PyPI url)
- remove support for Python 2.6 and 3.3
- update README for Python and module support
- update README with Read The Docs badge
- update documentation
- handle production of NaN during angle calculations
- fix bug with PBs frequency map generation for < 20 residues