Update `arakoon.odocl`

The modules listed in `arakoon.odocl` were no longer up-to-date. Some were
listed but are no longer present, others were missing.

This commit updates the file, so API documentation can be built again using

```
$ ocamlbuild -use-ocamlfind arakoon.docdir/index.html
```

The file was generated using

```
$ find src/ -iname '*.ml' -exec basename {} .ml \; | \
    sed 's/./\U&/' | \
    grep -v -e _test$ \
            -e Bs_bench \
            -e OUnit_XML \
            -e Plugin_update_max \
            -e Profile \
            -e Test_utils | \
    sort > arakoon.odocl
```
Merge pull request #417 from Incubaid/update-odocl

Update `arakoon.odocl`
Remove duplicate license text
Merge pull request #418 from Incubaid/fix-LICENSE

Remove duplicate license text
Update README

Add some formatting and links, and rephrase some sentences.
Remove unused `String_extra` module
Merge pull request #420 from Incubaid/remove-string_extra

Remove unused `String_extra` module
implement custom optimize
grrr camltc
fix qshell extension for node ips list
fix test_db_optimize
Merge pull request #419 from Incubaid/update-readme

Update README
fix tests
fix test_restart_master_long
Merge pull request #422 from Incubaid/fix-ips-list-1.6

fix qshell extension for node ips list
Merge origin/1.6 into 1.6-for-1.7 (using imerge)
unlink safely to avoid TOCTOU bugs
match () iso _
Merge pull request #424 from Incubaid/test-restart-master

fix test_restart_master_long
removed a few hundred unused vars.