Cleanup tree

These commits remove some old and unused files from the tree:

- *ROOT/OCAML/include/event.h*, most likely added by accident.
- *src/client/c/*, the deprecated C client.
- *src/client/php/* and *jenkins/php/*, moved into @Incubaid/pharakoon
- *hudson/*, containing some old and seemingly unused CI scripts.
- *tools/patch.lwt_io* since we use upstream Lwt for quite a while.
- *tools/check_and_fix_tlog_8.2_to_0.1x.0.py*, since 0.8 and 0.1x have been unsupported for quite a while.

I will run everything through CI first to make sure no jobs break. This is more of a heads-up.