Improve CodePen Examples

[micahalcorn]

Now that CodePen examples have been added, they need to be less fragile. They currently detect whether or not the reader has a web3-enabled browser and, if not, suggest MetaMask. They don't, however, detect whether or not a MetaMask user is signed in, or validate the currently-selected network. To resolve this issue, fork each of our CodePens and add the following:

• Move web3 detection into another Pen that is added as an "external resource" in each forked Pen
• In the external Pen, detect that web3 is set to the Rinkeby network validation and serve an appropriate message if it is not
• In the external Pen, detect that a web3 account is available and serve an appropriate message if it is not

[jpvajda]

@micahalcorn I could probably get this issue pretty close to resolved, but may need some help if you want me to give it a shot, let me know.

[micahalcorn]

@DanielVF are we still going to have the CodePen examples in our new docs, or will this no longer be relevant?

[DanielVF]

I don't think so. It seems like they are really easy to get out of date.

[micahalcorn]

🆗 I'll close this for now and revisit the idea once our platform is more stable. Thanks @jpvajda for bringing this one to our attention.