DB changes for issue 215

This adds the `study_id` column to the `analysis_samples` table as discussed in issue #215. This also adds the two columns to the analysis_filepath table that were discussed in the Tuesday meeting. All objects and test data are also updated to reflect these added columns.
The ability to have ProcessedData objects with no files/null files and the ability to check if the ProcesseDData is null or not.

On Aug 17, 2014, at 11:28 AM, josenavas wrote:

> In qiita_db/support_files/qiita-db.sql:
> 
> > @@ -872,11 +880,13 @@ COMMENT ON COLUMN qiita.analysis_job.job_id IS 'Id for a job that is part of the
> >  
> >  CREATE TABLE qiita.analysis_sample ( 
> >  	analysis_id          bigint  NOT NULL,
> > -	processed_data_id    bigint  NOT NULL,
> > +	processed_data_id    bigint  ,
> Sorry, which changes I have to do? I think those changes has to be included on this PR...
> 
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