First commit!

We can do the following:
- create GStreamer elements
- create GStreamer pipelines
- add elements to a pipeline
- link elements of a pipeline
- change the state of an element
- initialize GStreamer
- deinitialize GStreamer
Create .gitignore file.
Implement val Gst.print_version: unit -> unit.
The Makefile now produces static libraries.
Merge branch 'master' of github.com:antoine1fr/gst.ml