Merge pull request #2 from knocte/master

metadata fixes around last committed fixups
Iterator: Try resetting value before usage
Iterator: Next try to fix crashes
dllmap: Fixed mapping for glue library
DynamicSignal: Fixed glue code name
Gst.Object: fix creation of GValues for property setter in custom code

The GValue needs to hold the type of the value, it's not related to
"this" or "property".
Gst.Object: add some pre-validation to property setter