dev-modular should be completely merged into mmap-dev branch

Currently, this tool can take a set of temporary, uncompressed log
files on a given node, and combine into a single darshan log.
Next step would be to modify this code to perform shared file
reduction logic to combine per-node log files into per-job log
files.

Now, register_record() accepts an argument for the size of
the record being registered, and this is used to track how much
data each module has stored in their allocated memory region.