Search functionality for GET and POST
Before implementing CQL, only GET search was supported. This is still checked in the code, but now it seems to be a mixed bag and POST may actually not be supported although the browser tries to use it. We should check for both options, and use whetever is available. POST preferred. For this we need to support building queries for both GET and POST.
cc @rowanwins
Actually, I just realized that the new item filters always post to the search endpoint. but that's not always the intended behavior, I think. You should be able to do a get request with queryables to the items endpoint. So we really should do GET and POST support. The /items endpoint defaults to text, and we should let /search default to POST and fallback to GET, I assume.
Edit: I implemented a first basic version of CQL text and disabled POST for now, although MS PC doesn't really seem to handle CQL text well. Needs further testing and we need to better implement POST and GET altogether. We need to better check the capabilities, e.g. conformance classes for CQL (related commit in another branch: 9fcbae7f), allow GET and POST in search link detection and then handle it correctly in the code so that always the supported case is used. This is quite a bit of work still...
Let's release GET functionality in beta.1 and then head for GET and POST in the next release.
Implemented in #315