Moved mocha options to mocha.opts file

Setting all command line flags from `npm test` mocha command in
`mocha.opts`. Now using nyan reporter bc d'aaaaawwww.
Dustcore js file is now dynamically found.

Added two test cases to check if dustcore file path is correct - check
if it contains the core node_modules path and the version number.
Getting the path to the module via `require` and the version number via
the `package.json` file for `dustjs-linkedin`.