Extend system-info with information about OIIO, OCIO and OSL

Summary:
Version of those libraries might be useful to know.

- OIIO and OCIO is exposed via bpy.app.oiio and bpy.app.ocio.
  There're "supported", "version" and "version_string" defined
  in those modules.

- OSL is available as _cycles.osl_version and _cycles.osl_version_string.

Reviewers: campbellbarton

Reviewed By: campbellbarton

CC: dingto

Differential Revision: http://developer.blender.org/D79

intern/opencolorio/fallback_impl.cc

@@ -431,3 +431,13 @@ void FallbackImpl::finishGLSLDraw(OCIO_GLSLDrawState * /*state*/)
 void FallbackImpl::freeGLState(struct OCIO_GLSLDrawState * /*state_r*/)
 {
 }
+
+const char *FallbackImpl::getVersionString(void)
+{
+	return "fallback";
+}
+
+int FallbackImpl::getVersionHex(void)
+{
+	return 0;
+}