GET solves with cache-control

[sbaer]

rhino.compute.exe should expose a GET endpoint for solving that takes the json as a querystring when the string is short enough. This must include the hash of a definition so we don't get bad cache hits. The GET requests should support cache-control to improve the chances that a user of Hops won't even need to hit a server in some cases.

[mcneel-build]

Linked with COMPUTE-188

[sbaer]

Along the same line we should see if POSTs will support cache-control when used with Hops. What I've read online is confusing and it would be easiest to just test this out.