Better filtering system

[robxu9]

Right now, the filtering is explicitly coded in. We need a better filtering system, preferably like the way pages are filter - get parameters.

Since golang does NOT support a filter scheme like filter[something]=something, we'll have to hardcode keys. Which won't be too bad.

Could do:
?status=testing
?page=x (already done, of course)
?before=date
?submitter=email
?name=name
?arch=arch
?repo=repo

[robxu9]

also now ?platform=platform
now marking highlyrequested