update old ObsPy version number use in two places
Changelog for 0.8.4
deb: manually remove one .gitignore during packaging

no idea why it gets included in the package building process in the
first place. several other .gitignore files get excluded automatically.
Throw verbose exception if no data has been added before plotting
Merge pull request #591 from bmorg/ppsd_plot_exception

Throw verbose exception if no data has been added before plotting
quakeml: reset patched RelaxNG schema

 - official version again (which has been fixed)
 - basically QuakeML-RT tags are now allowed as valid foreign tags
   (as is tolerated by QuakeML developers)
deb packaging: avoid problems/workaround with https and SSL
obspy-plot: option "-o" for direct output to file (via
Stream.plot(outfile))
trivial helpstring change
Numerous improvement to the event plotting.

* Plotting just a single event now supported for all projections/color
  encodings.
* Color encoding now defaults to the event depth.
* New colormap for the event depth encoding.
* Now uses the preferred magnitude and origin if available.
* Colorbar hidden for single events.
* Adjustments to the map colors for better visibility of the events.
* Some bugfixes and workarounds.
Plotting of record-sections added
PEP8 cleanup
Update credits.rst (#598)

- 'Contributers' --> 'Contributors';
- Added a few new contributors from https://github.com/obspy/obspy/graphs/contributors ;
- Still need to figure out the actual name of some of the remaining unlisted contributors.
Update credits.rst (#598)

Also crediting Peter for his work on ObsPy wiki.
Update credits.rst (closes #598)

This should close #598.
Waiting for new contributors to come!
Added example script and brief tutorial, filed suggestions
Fixed Typos
Merge pull request #601 from miili/master

Plotting of record-sections added
Update credits.rst
Updated credit.rst