db: added in method to get obs table entries.
db: added function to get get processing times for all jobs matching query
job_info: update page to show obs info if available.

Also rearranged the existing charts a little.
db: find_jobs has option to filter on obsquerys

Note that this rather unsafe at the moment as it doesn't
sanitise the strings used for the obs query.
job_list: job_list can filter on obsquery options
tile_list page: now lets you filter tile list on observation pars.

Also moved the filter form into a macro.
css: improve job info page
job_info: added in obs information to html template
db: bug in find_jobs with count

Possibly dodgy bug fix -- find_jobs with count=True doesn't
always work if join is being used. Fix just removes the group
by clause, but this could return an unexpected number of results
potentially.