[rest] Allow colons in SSE topics filter

[falmanna]

fixes #1043

[cweitkamp]

Thanks. Can you please sign-off your work?

It would be nice to have some unit tests for the new pattern to cover at least all available core events. May I ask you to add them?

[falmanna]

I signed off the work and added some tests for the single entity filter.

[cweitkamp]

Unfortunately the test failed https://travis-ci.org/openhab/openhab-core/jobs/591061769#L2130 - It looks like the dash ("-") is not allowed too:

[ERROR] Tests run: 4, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.24 s <<< FAILURE! - in org.eclipse.smarthome.io.rest.sse.internal.util.SseUtilTest
[ERROR] testValidInvalidFilters(org.eclipse.smarthome.io.rest.sse.internal.util.SseUtilTest)  Time elapsed: 0.139 s  <<< FAILURE!
java.lang.AssertionError: 

Expected: is <true>
     but: was <false>
	at org.eclipse.smarthome.io.rest.sse.internal.util.SseUtilTest.testValidInvalidFilters(SseUtilTest.java:56)

[ERROR] Failures: 
[ERROR]   SseUtilTest.testValidInvalidFilters:56 
Expected: is <true>
     but: was <false> 
[ERROR] Tests run: 4, Failures: 1, Errors: 0, Skipped: 0

[falmanna]

That's strange, why did it pass when I ran it locally in Eclipse?

[falmanna]

Okay, apparently I didn't rebuild the bundle before running tests.

Should I add another commit? or modify the previous?

[cweitkamp]

LGTM. And thank you very much for your first contribution over here.