Update to use pyyaml safe_load(), as load() is unsafe and disabled on some systems

AUTHORS

@@ -11,6 +11,7 @@ Dmytro Katyukha
 Gerard Marull-Paretas
 Hark
 Joel Lehtonen
+Justin Vieira
 kennedy
 Kristi
 ldos

src/escpos/capabilities.py

@@ -38,7 +38,7 @@ else:
 if full_load:
     logger.debug('Loading and pickling capabilities')
     with open(capabilities_path) as cp, open(pickle_path, 'wb') as pp:
-        CAPABILITIES = yaml.load(cp)
+        CAPABILITIES = yaml.safe_load(cp)
         pickle.dump(CAPABILITIES, pp, protocol=2)
 
 logger.debug('Finished loading capabilities took %.2fs', time.time() - t0)