Adds ocaml-sqlite3EZ and its dependency ocaml+twt

ocaml+twt is an alternative syntax for OCaml that uses indentation to group
multi-line expressions, like Python and Haskell.

Homepage: http://people.csail.mit.edu/mikelin/ocaml+twt/

sqlite3EZ is a thin wrapper for sqlite3-ocaml with a simplified interface. Query
results are processed with a functional map/fold, transactions are
aborted by exceptions, resource management is handled by the garbage
collector, etc.

Homepage: https://github.com/mlin/ocaml-sqlite3EZ
Merge remote-tracking branch 'upstream/master' into ocaml-sqlite3EZ

Conflicts:
	pkgs/top-level/all-packages.nix
ocaml-twt: some fixes
Merge pull request #3712 from vbgl/ocaml-sqlite3EZ

Adds ocaml-sqlite3EZ and its dependency ocaml+twt