Add browser field

[wclr]

to support browserfy and other loaders that use browser field for resolving browser version
https://github.com/substack/node-browserify#packagejson

[lukeapage]

thanks.

[jonnor]

I suspect that this actually breaks browserify support...
When depending on less in another project, and there using browserify to bundle my project, I get:

Running "browserify:src" (browserify) task
>> Error: Cannot find module './utils' from '/home/jon/work/thegrid/taylor/node_modules/less/dist'

Not having such problems with 2.4.0

[wclr]

@jonnor but without it browserfy will require node-version. There is not need parse dist ready browser version There noParse option to skip parsing of require statements.