Add a travis.yml to test a build.
Mac support in travis.yml
Add a vim function to indent extern "C" right

cindent indents 'extern "C" {' based on the opening {, so this adds a
function as indenter that detect extern "C" and overrides cindent for
that case.

This also adds a example line on how to reindent all code with vim.

Signed-off-by: Anton Lundin <glance@acc.umu.se>