Rename .browserify.js to .common.js

Browserify is not the only CommonJS implementation, so this is a better
name for this file

Refs glittershark#46

Author: glittershark

Gruntfile.js

@@ -13,7 +13,7 @@ module.exports = function(grunt) {
         react: {
             compile: {
                 files: {
-                    'build/reactable.browserify.js': 'src/reactable.jsx',
+                    'build/reactable.common.js': 'src/reactable.jsx',
                     'build/tests/reactable_test.js': 'tests/reactable_test.jsx'
                 }
             }

README.md

@@ -28,8 +28,8 @@ Or, you can just download the raw file
 
 That file exposes a global object `Reactable`. If you'd rather use browserify or
 another CommonJS implementation to `require()` it, there's a file
-`build/reactable.browserify.js` in the repo or 
-[here](https://github.com/glittershark/reactable/raw/master/build/reactable.browserify.js)
+`build/reactable.common.js` in the repo or 
+[here](https://github.com/glittershark/reactable/raw/master/build/reactable.common.js)
 if you'd like to download it directly.
 
 Keep in mind that we depend on the latest version of React (0.11), **with