Build signal_proc_lib as a .so and link with code

[atom2626]

Currently, some functionnalities of signal_proc_lib has been copied and pasted in sections of the IntelliPi (i.g. preprocessing).

This library should exist as a shared object and be linked to the project.

[alexvjoseph]

created and linked a shared object for a sample code on ubuntu 14.04.3 LTS, need to replicate the steps on custom image

[alexvjoseph]

Converted the library as shared object and linked with a sample code while on cross compiling stage and tested the generated executable on target

[zimbob10k]

Please add - checkin/commit information so we can track this feature

[alexvjoseph]

Please note the check-in/commit information,

https://github.com/AtlantsEmbedded/IntelliPi/tree/feature/shared_objects