Checking for virtual memory errors in token reallocs
Returning NULL for list_peek on empty list
Using real paths and changing to files' directories

Necessary to support relative include files
Better handling of unterminated quotes
Updating header
Adding test files
Adding explicit -std=gnu99 to Makefile
Updating tasks
Generating clex.h in Makefile
Moving unterminated quote test to test/fail
Passing cleanup function to list_destroy
Adding list_size public prototype
Adding list test code