Optional params

[mattpass]

Allow merchant to set optional params alongside wallet, amount and description.

Ideas could include:

• Num confirms needed
• Approval on recognition
• Dev mode on/off (on = use widget.js instead of widget.min.js)
• Button type and style

...and others

Document these as optional params and the only mandatory params are wallet, amount and description.

[mattpass]

Optional params are already being implemented and the 4 mentioned above are already covered, aside from dev mode on/off. Closing issue.