First version of malloc wrapper.
added a wrapper around free().
Added panic function.
Added documentation about xmalloc and panic.
Added panic on out of memory errors.
Stylistic + doc changes.
Change mutex and semaphore mocks to xmalloc().
Added panic context (file and line number).
Updated documentation.
xmalloc : Added special case for size == 0.
Forgot sizeof(int)...
Malloc doesn't always return NULL.

This is not part of the C standard and glibc behaviour actually differ.
Added a wrapper for realloc
xmalloc: refactored tests.
Merge pull request #24 from antoinealb/malloc-wrapper

Malloc wrapper + Panic function