Remove dead code

(cherry picked from commit 2babbfbdbaef2d6c41ad8fa1ec287bf5db7b52b7)
Enable compiler warnings

This commit enables compiler warnings, disables some somewhat-harmless warnings
which we encounter often throughout the codebase (for now), and sets warning 33
('Unused open') to 'error'.

Next to enabling the compiler flags, fixes for unused open statements are made
as well.

(cherry picked from commit 7b2044ad826c073aa855420f6753f976b4e2a29e)

Conflicts:
	src/plugins/registry.ml
Enable warning 32 "Unused value declaration"

Remove some more dead code.

(cherry picked from commit ee74526481674c28699840fd8703d055fe86eee4)
Enable all warnings, most as errors, and fix errors

(cherry picked from commit d03a5d56c0fd81a0f8527fb05b4e0754612c1048)

Conflicts:
	src/client/common.ml
Re-instate 'bisect' builds

This requires some `ocamlbuild` massaging.

The `maybe_use_bisect` trick is a cludge to select all files except
`logger_macro`.

Not a beauty, but it works.

(cherry picked from commit de6943e6bb554fe6e8ee36c63acbf38e7e5cd064)
Remove unused `Catchup.store_tlc_cmp` type

Noted by @domsj in #406.

See: https://github.com/Incubaid/arakoon/pull/406#discussion_r12524763
Merge pull request #408 from Incubaid/remove_dead_code

Remove dead code