The program can now be started by one of the three following ways :
- main : No arguments, the program will ask the user the universe
settings.
- main <path_to_custom_data_source> : Create the universe with our
custom file "format".
- main <number of dimensions> <number of cluster> <path_to_data_source>
: the same as 'no arguments' but they're specified directly.

Added a 'dimensions' property for the universe in order to know the
size of a data. This is required for saving each dimension value of a
point.

Added the signature of the 'remove_string_trailing_newline' method in
the 'files_utils.h' file.

Updated the 'open_file' method by adding a mode parameter.

Renamed some variables for more clarity.

The universe can now be created from data in a text file.

Added the files_utils who contains methods to open a file, count the
number of lines and remove trailing newline.

Added methods to create an empty kmeans universe and to initialize
empty clusters array and points array.

Added a method who create a point from a line in the text file.

Fixed a memory leak caused by non freed point value.

In kmeans.h :
    - Fix some missing pointers.
    - Swap the destroy_point and destroy_cluster.

In kmeans.c :
    - Add allocation and free for kmeans, point and cluster create
    methods.
    - Add the signature of the other methods.

In main.c :
    - Add some code to test the allocations.