Trac_168: added some helper functions for logging functionality
added a sample logging config file
Merge branch 'master' of https://trac.orr.noaa.gov/git/PyGnome into log
Added  max water emulsion fraction to Oil database object.
uncommented the slow marker on tests
updated 'mass_balance' attribute to 'weathering_data', this will contain
intrinsic properties like 'density', 'viscosity', etc
- added density, amount_released, floating to weathering outputter
- changed mass_balance to weathering_data
Merge branch 'master' of https://trac.orr.noaa.gov/git/PyGnome
changed name 'mass_balance' to more general 'weathering_data'
added additional output properties: avg_density, floating, amount_released
fix kml output option to delete file if it exists and let user pick file name
Merge branch 'master' of https://trac.orr.noaa.gov/git/PyGnome
- updated _bind_db_session to _get_db_session
- this now returns an instance of the DBSession() object
reverted get_oil so it doesn't return the session object. This should
not be needed once the record is retreived.
Merge branch 'master' of https://trac.orr.noaa.gov/git/PyGnome
- changed weatherers to update 'mass_components' array in place
- model just sums this up to update 'mass' array at end of weathering
  loop
- added fake uncertainty in output
- changed spill_container to always write weathering data -- currently,
  this will be 0.0 if no mass is given
updated tests
- updated so weatherer changes 'mass_components' and sums up for 'mass'
  array. Not as efficient as letting model do it, but keeps the two arrays
  in sync
- updated 'Process' base class so 'active' attr is initialized to value
  of 'on' instead of always initializing to True. This is base class for all
  movers and weatherers
- reduced nested dict level by one for WeatheringOutput
- added _include_weather_data flag in SpillContainer that gets set to
  True in prepare_for_model_run if at least one spill contains a spill
  'amount'. This is just so we don't get 0.0 for 'floating' and
  'amount_released' for each step if we're not doing weathering.
- added mock objects for modeling Skimmer, Burn, Disperse processes -
  still need tests
- updated Evaporation so prepare_for_model_run sets 'avg_density' using
  default 15C temp if no Water object is defined. Setting intrinsic
  properties should get moved elsewhere but to something that has access
  to Water object (temp)
- updated tests
uncommented some tests
was using the wrong schema for weathering modules - fixed this
Moved the Categories object to be linked with Oil and not ImportedRecord
Removed the viscosities() function from oil_library.utilities,
as it is not needed anymore.