allow require.resolve('bootstrap') to work under node
added 'main' field to package.json
added a separate npm-specific main file
generate commonjs/npm entrypoint module via grunt task
Merge remote-tracking branch 'upstream/master' into node-requirable

Conflicts:
	Gruntfile.js
pulled output path out to gruntfile
code style fixes
added banner about generated file
code style improvement
Merge pull request #13824 from jsdf/node-requirable

Allow npm package to be resolved via node module resolution