Link to jackjack-jj's fork of pywallet

With Joric's fork untouched for a year, it might be better to point people to jackjack-jj's pywallet fork.
Merge pull request #26 from fanquake/patch-1

Link to jackjack-jj's fork of pywallet
Merge pull request #25 from nelisky/tweaks

Tweaks to allow using a subset of the lib and altchains
b58encode: speedup.
Avoid exception on invalid script.
Merge pull request #30 from jtobey/abe-tweaks

Abe tweaks
Better error handling