Memory leak

The function static decode_aux *_make_decode_tree(codebook *c) in the 
file "SharedBook.c" has a major memory leak. It calls calloc() twice, 
storing the pointers to ptr0 and ptr1. However, nowhere in the code is 
there a call to free(). As a result, this function will leak the two blocks of 
memory every time it is called.

Should be a 15 minute fix.