Support multiple jiras

[chrisenitan]

Addresses #14

Changes

• Using @timbru31 idea on Support for multiple JIRAs #14 (comment)
  • It accepts 3 more url and id strings from options form: extendable by number value parsed to integers
  • It stores arrays of these jira urls and an array of unique id for each one
  • It saves last used jira link on handleSubmit
  • It selects last used jira link on renderDialog
• I added some placeholders and other minor UI hints

Others

• not sure if the name company is whats chosen
• Should autocomplete be turned off for the options input field..

I just found and loved this extension and needed this feature so I thought it'll be a good idea to help myself and all the other users on it.

[timbru31]

Thanks for the work - will take a closer look at it, soon! :)