Fetching different types of PR's using ajax

[deepak-bharti-deel]

Profile page of student/mentor has different types of prs. Currently all the prs are being fetched in once and only the relevant prs are being shown using show and hide javascript functions. It's not a problem now but with increasing number of prs for a user, this will become very in efficient. So fetch corresponding prs only when user request for them and then these can be further updated using ajax.