Improve js patch

[nand2]

Hi!

This PR improve the javascript patch in the following ways :

• Fix the web3:// to https:// conversion when the A tag has elements inside (e.g. <a><span>text</span></a>)
• Now respect the targetattribute of the A tag (target="_blank" open a new tab)
• Add support for altering the src attribute of IFRAME tags : convert from web3:// to https://

[syntrust]

Hi nand,
The change looks good to me.
I was just wondering should the patchHTMLFile be improved continuously, is it a good idea to make it a standalone module outside the protocol part? Hopefully, this is not the case.