gstreamermm 0.9.5

gstreamermm provides a C++ API for the gstreamer streaming multimedia
framework. There is lots of work still to be done, but we have working
examples that play video and music.

Changes:

gstreamermm 0.9.5 (unstable):

* Bin: Added properties and vfuncs.
* ChildProxy: Added properties and vfuncs.
* Clock:
  - Added get/set_calibration().
  - Added properties and vfuncs.
* Element:
  - Added found_tags() and found_tags_for_pad(), create() and parse().
  - Used ArrayHandle<> for methods that return an array of QueryType.
  - Added vfuncs.
  - Derive from Gst::Interface.
* Added GhostPad
* Index: Added signals and properties. Made IndexEntry::assoc_map()
const.
* Added MessageTag.
* Pad: Added add_{data,buffer,event}_probe() methods.
* PadTemplate: Wrapped members name_template, direction, and presence.
* Parse: Throw errors as exceptions.
* Pipeline: Added properties.
* Structure: Renamed is_empty() and get_size() methods to empty() and
size(), 
  for consistency with the standard C++ library.
* Added TagList.