Add watch option to reload API

[shavo007]

Creating a new issue just to keep tabs. #120

Related to the above pull request.

Need an option in drakov.run to watch the md files and reload.

Similar to:

grunt.registerTask('mock-api', 'Start drakov server', function() {
var done = this.async();

var drakovOptions = {
  sourceFiles: './doc/*.md',
  serverPort: 3000,
  autoOptions: true,
  delay: 1000,
  watch: true
};

drakov.run(drakovOptions, function(err){
  console.log('-- STARTED --');
  if (err) {
    throw err;
  }
});
done();
});

[yakovkhalinsky]

I believe this is a limitation of our current watch implementation, which only currently works from the CLI

Something to consider for a future update I think

[emileber]

It would be best if it was documented (in the root readme) that this is not yet available from the option object passed to .run.