vidjil: release 2014.09
Makefile: Launch create-git-version.sh only if it exists (and can be executed)
Algo: Add virtual destructors when needed.

That solves ``deleting object of polymorphic class type * which has
non-virtual destructor'' GCC warnings.
Algo: Use unsigned loop variables when needed

That solves signed/unsigned compilation warnings.
This had no effect in practice but that makes the compiler happy.
Algo: Cast so that we compare the same (un)signed types.
Algo: Removes unused declarations

Makes the compiler happy too.

This, together with commits d0ccbac 4c5a51d and 61c5c49, solves all
compilation warnings except the ones coming from an unused parameter (which
can make sense).
Tests: Sequence has a new field, which must be initialized too
Algo: json_samples was not deleted

Caused a minor memory leak. Corrected.