Import todotxt-2.10nb20140521 as wip/todotxt.

A simple and extensible shell script for managing your todo.txt file.
Snapshot 20140518.
This commit has a working Graphite by using cloog+isl from gcc/infrastructure
but I will change it to not build with gcc-graphite by default after the
commit. See TODO for details.
Imported wip/todotxt