Use OCaml 4.02.1 in the Travis build.
Merge pull request #192 from yallop/travis-4.02.1

Use OCaml 4.02.1 in the Travis build.
Update Travis build script for 4.02.1
add windows support
rewrite without pipe operator
AppVeyor: basic build configuration.
AppVeyor: patch findlib to use Unix.system instead of Unix.create_process

Unix.create_process fails with status 127 under Cygwin.
AppVeyor: build and run the tests.