Update mixins.json

Removing BTO and AMAD from the reg-ex for biosample_term_id
Update biosample.json
Update biosample.json

Removing BTO from the test set
Update experiment.json

Removing BTO from the test data
Change promoter property name in construct as per lab request
Merge pull request #298 from ENCODE-DCC/1516-No_more_BTO

1516 no more bto
Merge branch 'master' of https://github.com/ENCODE-DCC/encoded
Property name change in construct test insert
Merging in master.