Adds CORS filter and Functional test

[eMaringolo]

I implemented a basic CORS filter with a functional test (including setting up a separate server adaptor to handle cross-origin requests).

It would be great to merge this into the upcoming release, so it can be ported to VAST (and other dialects).

[eMaringolo]

This solves #1270

[eMaringolo]

@jbrichau Can this be merged? :-)

[jbrichau]

@jbrichau Can this be merged? :-)

Sorry for the unresponsiveness. I'm swimming in too much things at once. I will test this hopefully this week!

[jbrichau]

@eMaringolo I did not notice before that the Gemstone builds are failing here. This is probably because of incompatibility. We will need to fix this before this can be merged.

[eMaringolo]

@jbrichau But the incompatibility is caused by something else, right? Looking at the job details, the failing tests have nothing to do with my proposed changes, or do they?

[jbrichau]

The failing tests are testSentButNotImplemented and testUndefinedSymbols. These tests fail because there is code added that sends unimplemented messages and references undefined symbols.

I'm guessing it's in the example code, which is not part of a test so no other tests will fail.

expandMacrosWith: is probably the unimplemented message in GemStone.

[jbrichau]

@eMaringolo I merged this in a branch to be able to debug and fix the broken tests in GemStone.

[eMaringolo]

Thank you very much Johan!