Changed cleanup of cached decompressors to manual

setup.py

@@ -42,7 +42,7 @@
 setup(
     name="jpeg4py",
     description="libjpeg-turbo cffi bindings and helper classes",
-    version="0.1.1",
+    version="0.1.2",
     license="Simplified BSD",
     author="Samsung Electronics Co.,Ltd.",
     author_email="a.kazantsev@samsung.com",
@@ -61,6 +61,8 @@
         "Programming Language :: Python :: 3.2",
         "Programming Language :: Python :: 3.3",
         "Programming Language :: Python :: 3.4",
+        "Programming Language :: Python :: 3.5",
+        "Programming Language :: Python :: 3.6",
         "Topic :: Software Development :: Libraries"
     ]
 )

src/jpeg4py/_py.py

@@ -68,7 +68,7 @@ def __init__(self, lib_):
     def get_last_error(self):
         """Returns last error string.
         """
-        return ffi.string(self.lib_.tjGetErrorStr()).decode("utf-8")
+        return jpeg.ffi.string(self.lib_.tjGetErrorStr()).decode("utf-8")
 
 
 class Handle(Base):
@@ -92,9 +92,6 @@ def release(self):
             self.lib_.tjDestroy(self.handle_)
             self.handle_ = None
 
-    def __del__(self):
-        self.release()
-
 
 class JPEG(Base):
     """Main class.
@@ -117,6 +114,9 @@ class JPEG(Base):
     def clear():
         """Clears internal caches.
         """
+        # Manually release cached JPEG decompressors
+        for handle in reversed(JPEG.decompressors):
+            handle.release()
         del JPEG.decompressors[:]
 
     def __init__(self, source, lib_=None):