bindings/python/bt2: Make the bt2 Python bindings build

bindings/python/bt2: Make the bt2 Python bindings build

This patch is just a little bit more than the bare minimum to make the
Python bindings build (that is, configure with --enable-python-bindings
and build).  It consists of sync'ing the .i SWIG interface definition
files with the corresponding headers.  It's possible that the interfaces
are incomplete, in which case they'll be adjusted in the a later pass.
For example, output parameters are currently not named in a way that
match the type maps.

For simplicity, I have included at the same time some other changes to
the .i files, such as adjusting the typemap definitions (in
native_bt.i).  The helper functions (such as at the bottom of
native_bt_componentclass.i) are also changed to the "final" form they
have on my development branch.  Even though these are not immediatly used,
they need to be changed for the bindings to build.

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Change-Id: I87a438a692690639f956b214f878df65885ed78c