add a simple Makefile
make pebble app JavaScript be generated by Makefile
refactor JS build system

Make use of require.js to pre-compile all of the JavaScript nastiness.
ping the Javascript every 5 seconds instead of 15
move application javascript to src/js/app

This allows use of wildcards in the Makefile.
README.md: add note on requirements
Makefile: add 'build' as a dependency to 'install' target
replace minified proj4 with unminified version

We minify the output anyway so let's not have multiple layers of
obfuscation!
add proj4 licence text