[#121] Fix start-date documentation
[#121] And end-date and last-change to docs
[#121] Add extra filters to docs

participating-org.role and filters ending in  __gt and __lt
[#92] change _ref _text to .ref .text in transaction filters
[#124] add transaction provider to validators
use ckan action api for all calls instead of deprecated rest api
[#129] fix decimal error handling, sector/parcitipating org parsing

decimal error was not handled correctly causing the entire job to error
and skip over

it was possible for sector/paticipating org roles returned None instead
of the empty list, sqlalchemy errored at this point as None is not a
list-type
[#129] ignore none type in summation of transaction amounts
[#87][#129] delete old logs once a job finishes/errors

Change log deletion so that each job cleans up it's old logs instead of
update_activities deleting the logs first.

Delete old logs of "job iatilib.update_{job_type}" when that job_type
finishes. If an exception occurs in that job_type, clean up the old logs
before logging as well to prevent logging the same error over and over
again.
[#87][#129] move log deletion to beginning of function
Merge pull request #123 from okfn/121-filter-documentation

Add missing filters to documentation
Merge branch 'master' into 120-new-filters
[#120] Add provider/receiver activity id filters