add browser implementations for buffer and reader
add browserify + add pbfTest to browser test
add PBF browser example
Copy test.pbf to example folder because Firefox only allows XHR  for file:// URLs in same folder or subfolder.
don't check-in browserify bundle (osm-read-pbf.js) for now,
 because it's huge.
update readme's with browser info
Merge pull request #9 from nrenner/browser

add browser implementations