updates to fail early for required executables that are not in PATH

daemon/core/errors.py

@@ -0,0 +1,21 @@
+"""
+Provides CORE specific errors.
+"""
+import subprocess
+
+
+class CoreCommandError(subprocess.CalledProcessError):
+    """
+    Used when encountering internal CORE command errors.
+    """
+
+    def __str__(self):
+        return "Command(%s), Status(%s):\n%s" % (self.cmd, self.returncode, self.output)
+
+
+class CoreError(Exception):
+    """
+    Used for errors when dealing with CoreEmu and Sessions.
+    """
+
+    pass