Cleanup source_t codebase & fix usage

Previously SOURCE is overhauled with a dynamic array implementation,
but parser.c and inliner.c didn't actually benefited from it, and
could still cause overflow if size exceeds capacity.

In this patch, now extending source_t respects computed result size
and expands if need. inliner.c's implementation is now also replaced
with dynamic array implementation.

Additionally, few functions are renamed to keep function naming
convention.

Author: ChAoSUnItY