Convert LTTngTop to C++ and state system

Convert LTTngTop to C++ and state system

This commit integrates LTTngTop with a generic C++ state system.
This creates a cleaner code base as the analysis won't require any
ad-hoc state system anymore.
Since the library is in C++, this commit also converts LTTngTop
to C++, most of the code written in C stays the same.

New dependencies (that should be integrated in the tree) :
git://git.dorsal.polymtl.ca/~smarchi/libstate.git
git://git.dorsal.polymtl.ca/~frajotte/librbrntrvll.git

The code is not yet working, but it is close.

Signed-off-by: Pierre-Bernard Thiffault <pbthiffault@gmail.com>
Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>