Adjustments to builder_web.sh
Adjustments to builder_web.sh

Currently, if the `web` process crashes because of a CSS or JS complication error, which happens frequently during development, it takes down everything in the Profile with it. This tweaks a few things to prevent interference with builder-web development workflow:

* Always export NVM_DIR and source the NVM script
* Always install and use the locally specified Node version (NVM detects it automatically from .nvmrc)
* Build a bundle and serve it without watching for file-system changes (since we do this by running `npm start` locally)

Signed-off-by: Christian Nunciato <72baf27260399b834ebea61a03768908101e8432@chef.io>

nathenharvey/habitat,georgemarshall/habitat,habitat-sh/habitat,rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,rsertelon/habitat,nathenharvey/habitat,habitat-sh/habitat,rsertelon/habitat,georgemarshall/habitat,nathenharvey/habitat,nathenharvey/habitat,rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,rsertelon/habitat,nathenharvey/habitat,nathenharvey/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,georgemarshall/habitat,georgemarshall/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat