Add support for "lavascript" object on package.json

[mjstahl]

Add support for reading a "lavascript" property from package.json.

const pkg = require('./package.json')

if (process.argv.length < 4) {
  const lavascript = pkg.lavascript
  if (lavascript) {
    // get srcDir, and destDir from lavascript object 
  } else {
    // print usage
  }
}

[mjstahl]

I think it should have an order like so:

• If argv.length >= 4 -- use arguments
• If lavascript property in package.json, look for srcDir, and destDir properties
• else use src as the source directory and dist as the destination directory