snuffling: added some new methods

  get_markers
  get_event_markers
  get_selected_markers
  get_active_event_and_phase_markers
  pile_changed
  enable_pile_changed_notifications
  disable_pile_changed_notifications
fix for previous commit
seismosizer: added CLVD source type
Added documentation in snuffling.py
Merge pull request #30 from HerrMuellerluedenscheid/uplink

Added documentation in snuffling.py
snuffling: fixed some typos and improved some docstrings
improved a doctstring
pile_viewer bugfix: If a marker's event didn't have a name (None) goto failed

    Traceback (most recent call last):
      File "/usr/local/lib/python2.7/dist-packages/pyrocko/pile_viewer.py", line 3079, in inputline_returnpressed
        clearit, hideit, error = self.viewer.inputline_finished(line)
      File "/usr/local/lib/python2.7/dist-packages/pyrocko/pile_viewer.py", line 2970, in inputline_finished
        self.go_to_event_by_name(arg)
      File "/usr/local/lib/python2.7/dist-packages/pyrocko/pile_viewer.py", line 1987, in go_to_event_by_name
        if event.name.lower() == name.lower():
    AttributeError: 'NoneType' object has no attribute 'lower'
extended some documentation
Merge branch 'uplink' of https://github.com/HerrMuellerluedenscheid/pyrocko
snuffling: marker classes and functions now in snuffling namespace
included gmtpy
added topo stuff
added automap module
added automap app
gmtpy: pycdf -> scipy.io.netcdf
added geonames module
improved automap command line frontend
some tweaks to automap
autmap: added --download-etopo1 and --download-srtmgl3 options