bug hunt on new javascript file

I've made changes to the new JavaScript file and tested it.
#### new:
* 100% linted. No JavaScript errors.
* Controller manages it's own initiation through a function.
* model separated between model data, and temporary storage.
* reduced unnecessary functions and variables.
* basic sell functionality working.
* error catch now notices when bad stock symbols were entered.
* ...and probably a couple other little things.

#### outstanding:
* sell functionality does not handle removal when reaching 0 owned stocks.
* stocks still have no unique identifiers. only able to put one stock in the portfolio at a time.

Have fun! :tada: