Youtrack API changes seem to have broken this project

[marcreichman]

Exceptions keep showing up in my application.log like:

Failed to process
java.lang.RuntimeException: com.ontometrics.util.BadResponseException: Got response code 500 in response to https://XXXXX.myjetbrains.com/youtrack/rest/issue/byproject/XYZ?updatedAfter=1545152419412
	at com.ontometrics.integrations.sources.AuthenticatedHttpStreamProvider$2.handleResponse(AuthenticatedHttpStreamProvider.java:76) ~[AuthenticatedHttpStreamProvider$2.class:na]
	at org.apache.http.client.fluent.Response.handleResponse(Response.java:90) ~[fluent-hc-4.3.5.jar:4.3.5]
	at com.ontometrics.integrations.sources.AuthenticatedHttpStreamProvider.openResourceStream(AuthenticatedHttpStreamProvider.java:63) ~[AuthenticatedHttpStreamProvider.class:na]
	at com.ontometrics.integrations.sources.EditSessionsExtractor.getLatestEvents(EditSessionsExtractor.java:404) ~[EditSessionsExtractor.class:na]
	at com.ontometrics.integrations.sources.EditSessionsExtractor.getLatestEdits(EditSessionsExtractor.java:95) ~[EditSessionsExtractor.class:na]
	at com.ontometrics.integrations.jobs.EventListenerImpl.checkForNewEvents(EventListenerImpl.java:85) ~[EventListenerImpl.class:na]
	at com.ontometrics.integrations.jobs.JobStarter$EventTask.run(JobStarter.java:91) ~[JobStarter$EventTask.class:na]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_121]
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [na:1.8.0_121]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_121]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [na:1.8.0_121]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121]
	at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]
Caused by: com.ontometrics.util.BadResponseException: Got response code 500 in response to https://XXXXX.myjetbrains.com/youtrack/rest/issue/byproject/XYZ?updatedAfter=1545152419412
	at com.ontometrics.integrations.sources.EditSessionsExtractor.checkResponseCode(EditSessionsExtractor.java:369) ~[EditSessionsExtractor.class:na]
	at com.ontometrics.integrations.sources.EditSessionsExtractor.access$000(EditSessionsExtractor.java:54) ~[EditSessionsExtractor.class:na]
	at com.ontometrics.integrations.sources.EditSessionsExtractor$3.handleStream(EditSessionsExtractor.java:408) ~[EditSessionsExtractor$3.class:na]
	at com.ontometrics.integrations.sources.EditSessionsExtractor$3.handleStream(EditSessionsExtractor.java:404) ~[EditSessionsExtractor$3.class:na]
	at com.ontometrics.integrations.sources.AuthenticatedHttpStreamProvider$2.handleResponse(AuthenticatedHttpStreamProvider.java:74) ~[AuthenticatedHttpStreamProvider$2.class:na]
	... 13 common frames omitted```

If I go to that URL by itself, the youtrack system shows:

    <error>
    Parameter specified as non-null is null: method jetbrains.youtrack.rest.issue.IssueResource.getByProjectProject, parameter filter
    </error>


I found if I add a `filter` query parameter to this, even just `&filter=` it seems to not return the error. I'm not sure if this is a youtrack issue or an issue with this project but it's stopping me from functionally using this. 

Should I wait for commentary? Or should I just submit a PR with the empty `filter` parameter?