Fix under-flow bug in defsplitter. This led to infinite looping and out-of-memory errors when running on test inputs of less than (16 * num_cores) bytes (e.g. 128 bytes for an 8-core system).
The fix makes sure that each ma->length is at least one character wide.
Merge pull request #5 from ms705/master

Fix under-flow bug in defsplitter