Improvements to event system

Update cg_pack and events demo to use move semantics

Correct problem with SymPy

Correct issue #2

New customization features for C++ FIFO

New option for preventing custom buffer sharing

New callback mode

New version with improve duplicate mechanism when memory optimization…

… mode is on.

Correction to 1.9.2 and right version number.

Version 1.9.2

* Possibility ot assign a specific external buffer to a FIFO
* New option to allocate the FIFO buffer dynamically with custom allocator