Prevents zooming in the rendered html

[Kumuluzz]

Addresses issue #16

I came across the need to disable zoom in my DownView. I thought of two solutions:

1. Disable zoom per default
2. Inject a flag when initializing the DownView which enables/disables zoom

This pull request implements option 1) since I imagine this being the most common

[coveralls]

Coverage remained the same at 85.623% when pulling f06b270 on Kumuluzz:master into 43241e5 on iwasrobbed:master.

[iwasrobbed]

Hi @Kumuluzz 👋

I appreciate the pull request, but I'd rather not change the default zooming for everyone. I tend to prefer configuration with sensible defaults (more like your option 2).

Now that Down supports instantiation with a custom bundle, it might be best to just do it that way for now. If a lot of people end up wanting this, I'm happy to have another look later on.

[Kumuluzz]

Hi @iwasrobbed!

Do you think it would make sense if I update my pull request to have a predefined bundle that can be specified when initializing the DownView? Fx by expanding the init method with a allowZooming parameter:

public init(frame: CGRect, markdownString: String, openLinksInBrowser: Bool = true, didLoadSuccessfully: DownViewClosure? = nil, allowZooming: Bool = true)

Otherwise I can simply update my pull request to update the documentation on how to disable zooming 😊

[iwasrobbed]

Hey @Kumuluzz! I'd prefer just keeping this as a documentation update for now versus including an additional bundle for this one scenario. If it ends up being a widely needed feature, more people are welcome to comment on this to let us know. Thanks!

[Kumuluzz]

@iwasrobbed I'll update the documentation with some instructions then. Any preferences on where to place it? Just directly in the README below ### Options?

[iwasrobbed]

Maybe underneath the View Rendering section since it's specific to that area?