[TIDOC-1897] New validate script

Install dependencies:
~~~
sudo npm install -g js-yaml
sudo npm install -g colors
sudo npm install -g node-appc
~~~

Run validate script against titanium_mobile and see the errors generated:

Go to titanium_mobile/apidoc directory
~~~
node validate.js
~~~
or
~~~
node /path/to/titanium_mobile/apidoc/validate.js /path/to/titanium_mobile/apidoc
~~~

Review and merge in PR#6196

Rerun the validate script.  Errors should disappear.

Run validate script against module documentation.  Need to add the `-s` option or the script may fail with errors that it cannot validate.

~~~
node validate.js -s ~/projects/appc_modules/ti.map/apidoc/
node validate.js -s ~/projects/appc_modules/ti.coremotion/apidoc/
node validate.js -s ~/projects/appc_modules/ti.facebook/apidoc/
node validate.js -s ~/projects/appc_modules/ti.nfc/apidoc/
~~~