First entry in CONTRIBUTING.md

Notes about making database changes
Add patches directory
Update information on how to contribute patches
Merge branch 'master' of https://github.com/biocore/qiita into contributing_patches
Fix typo on 'Aproach'
Removing the study_id from the sample PK, and fixing populate.sql
Fixing small bug on logging the errors on the data object
Modifying the MetadataTemplate to prefix the sample names with the study id
Fixing the sample ids on the test OTU table
Modify analysis obj to reflect changes on the DB
fixing job tests
fixing search tests
fixing setup tests
Fixing remaining tests
Fixing support-files
Addressing comments
Merge pull request #536 from adamrp/contributing_patches

Contributing patches
Merge pull request #583 from josenavas/prefix-samples-study-id

Prefix sample names with study id