Repo initialization

Initializing repo with:
 - Headers of the abstract base data structures in include/
 - Source code in src/
 - Unit test modules in test/
 - Integration test modules in bin/
 - Recursive build system based on Makefiles
 - array_list data structure (dynamic array) defined but not
   yet tested

Signed-off-by: Raffaele Aquilone <aquiloneraf@gmail.com>