Trailing slash needed in baseApiUrl

[mrichar1]

Minor one - just noticed that baseApiUrl requires a trailing slash, since the code just does:

var resourceUrl = options.baseApiUrl + resourceSlug;

(which works when it's e.g. / but not for /api as documented.

Happy to put in a PR to fix this, but wasn't sure if you'd prefer the simple option of updating the documentation, or the fancier 'check for trailing slash, and add one if not present' option in the code.