Added sensible default for root directory

[wheresrhys]

So it's easier to use from the cli

Ac ouple of improvements which woudl help further woudl be

1. Ability to pass in root directory as a cli param
2. Read the root directory from .bowerrc if present and not overridden by config

[kornelski]

I don't see the CLI change.

Presence of root directory config changes how paths are interpreted, so you may need to change/delete code in other places: https://github.com/ftlabs/textrequireify/blob/master/index.js#L37 https://github.com/ftlabs/textrequireify/blob/master/index.js#L43

[wheresrhys]

I didn't add a CLI interface, but if you pass textrequireify in as a transform when using command line browserify using -t textrequireify it currently throws an error. Setting the root directory to a sensible default prevents this (at least when the project's bower directory is ./bower_components).

I'll edit those other two lines now