Windows File Path Fixes (#39)

* Added system_safe_path to convert paths to Windows

* Fix issue where engines would not be reported unless a system engine was installed

* Platform independent searching for binaries in engine directory

* Add missing package to requirements.txt

* Better error handling for ffmpeg.get_all_formats()

* Add system_safe_path to more locations in api_server.py

* Fix naming issue with Blender on macos

* Fix path lookups and add engine_path to workers

* Report installed renderers in status

* Remove files included by accident

src/render_queue.py

@@ -5,7 +5,7 @@ from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 
 from src.utilities.status_utils import RenderStatus
-from src.workers.worker_factory import RenderWorkerFactory
+from src.engines.engine_manager import EngineManager
 from src.workers.base_worker import Base
 
 logger = logging.getLogger()
@@ -100,7 +100,8 @@ class RenderQueue:
 
     @classmethod
     def is_available_for_job(cls, renderer, priority=2):
-        if not RenderWorkerFactory.class_for_name(renderer).engine.default_renderer_path():
+
+        if not EngineManager.all_versions_for_engine(renderer):
             return False
 
         instances = cls.renderer_instances()