Merge branch 'fix_issue_685' of https://github.com/antgonza/qiime into fix_issue_685
Added a SourceTracker tutorial rst file and image related to that tutorial
updated to use open-reference otu picking and core_diversity_analyses.py

need to make an udpate to qiime to use change from #741.
updated to use open reference otu picking and core_diversity_analyses.py
added check_id_map.py step
Merge branch 'master' of github.com:qiime/qiime into sourcetracker_tutorial
Removed example output from help command in order to avoid confilicts with changes to the option list in future releases.
added text to clarify the description of the filter_otus_from_otu_table.py
Improved the description of adding columns to the mapping file.
made a few minor changes to clarify descriptions and fix grammer.
Fixing --input_fps option for count_seqs.py. Not finished (currently does not support filepath pattern expansions)
Now requires minimum version of R instead of exact match, see issue #624
added the print_qiime_config.py command to the tutorial.
Fixing ci_type and metrics option type of conditional_uncovered_probability.py
Fixing test_alpha_diversity.py in test_pycogent_backports
Merge branch 'master' of github.com:qiime/qiime into conditional_uncovered_prob
Changing import from pycogent_backports.option_parsis to qiime.util
Merge branch 'master' of github.com:qiime/qiime into conditional_uncovered_prob
Added estimate_observation_richness.py module.

Also added corresponding test module with the start of an implementation (and tests) of AbstractObservationRichnessEstimator.
Added some utility methods needed by estimators.