Update Sketch View From RN

[gensc004]

• Added an image property that can be used by React Native to force an update to the native view with the new function setImage(image) where image is a base64 encoded string.
• Allowed for transparent background, and switched the default background from blackColor to clearColor.

Similar to what @stantoncbradley did in response to #6, I wanted to be able to draw on top of an image, and I also wanted to add the ability to undo lines that were drawn. I am working in RN ~0.40, so I opened this up against the react-native-0.40 branch.

[dkretsch12]

👍

[jgrancher]

Hey @gensc004,
Thanks for your help! Would you be able to rebase your changes from master please? :)

[gensc004]

Absolutely!

[jgrancher]

Hey @gensc004! I've finally merged #28, which means the module should now works on RN >= 0.40, directly from master. Would you be able to change your destination branch to be master, and rebase? Thanks! 💃

[bshyong]

^ looks great! would love to use this once it is merged

[HankieCodes]

My coworker @gensc004 and I cleaned up this PR with replacement PR #33, so we can close this one and continue discussing things over there.