[M72] Skeleton for JackD client
[M72] Basic ring buffer for jackd backend (due to its callback architecture)
[M72] Parser take jackd as an input type
[M72] Added help for jackd input
[M72] Implementation of jackd client, is bogus and segfault at start
[M72] Fixed errors

Segfault because waitbuffer offset was not brought back to 0 when the current buffer was pushed out.
Added wait in the fillBuffer loop in order to wait Jack when there's no more buffer to read
When interleaving different inputs, all buffers (except the first one) where blanked so we had only the first port working.
Merged the interleaving with the buffer reading in the callback.
[M72] Updated man page
[M72] Fixed visound jackd client name (for multiple instances)
[M72] Modified jackd_in_dropFirstBuffer to avoid concurrent call on in->jackd.waitbuffers when it's being replaced
[M72] Modified jackd_in_addBuffer to avoid concurrent call on in->jackd.waitbuffers when it's being replaced
[M72] Added some comments to clarify
SFML2 backend : replaced sprite by rectangleShape

Replaced the sprite by a rectangleshape for the remanence effect