Added new feature to dinamically debug libmalelf.
Now to get debug information from libmalelf simply set the environment
variable MALELF_DEBUG=1 and run the linked program. By default, the
output is on stderr.

Optionally, you can set the environment variable MALELF_DEBUG_FILE and
redirect the output to the selected file.
Added debug initialization to binary.c
Fixing possible buffer overflow.
Added basic unit tests to debug system.
Tests the environment variables usage.
Basic tests to avoid buffer overflows.
Added temp directory to tests. Used for log output files.