Check memory allocation

[AntoineGautier]

In algorithmRectangle.c the functions calculateLower and calculateUpper do not dynamically allocate memory to struct data lower and struct data upper.
It is neither done in compare.c which invokes those functions, see https://github.com/lbl-srg/funnel/blob/master/src/compare.c#L210-L212.
This will likely lead to stack overflow in case of large arrays.

EDIT: The memory allocation for the member arrays is done in removeLoop.

This issue must:

• Check all memory allocations throughout the code: is it even done? Is it checked for success before assignment? Is it freed eventually? Is free always used to free memory actually allocated dynamically with malloc?
• Check that potentially large data struct are passed systematically by reference rather than by values.