Assign frame ranges to servers based on their CPU count (#19)

* Expose renderer availability in status api

* Remove redundant is_available_for_job API call

* New server split logic by cpu and moved to server_helper.py

* Remove old dead code

* Add RenderStatus.WAITING to proxy categories

lib/render_queue.py

@@ -5,6 +5,7 @@ from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 
 from .workers.base_worker import RenderStatus, BaseRenderWorker, Base
+from .workers.worker_factory import RenderWorkerFactory
 
 logger = logging.getLogger()
 
@@ -81,7 +82,10 @@ class RenderQueue:
         cls.session.commit()
 
     @classmethod
-    def is_available_for_job(cls, renderer, priority):
+    def is_available_for_job(cls, renderer, priority=2):
+        if not RenderWorkerFactory.class_for_name(renderer).engine.renderer_path():
+            return False
+
         instances = cls.renderer_instances()
         higher_priority_jobs = [x for x in cls.running_jobs() if x.priority < priority]
         max_renderers = renderer in instances.keys() and instances[renderer] >= cls.maximum_renderer_instances.get(renderer, 1)