Revert web update commits; not ready for production, so moving to branch
according to README, lineman was supposed to be installed globally,
rather than locally, however this would be impossible without root.
Anyway let's use $BITSHARES_ROOT as a base dir, like it is for all
other prerequisites, instead of installing it deep into source tree
Add timestamp to web update signature; still needs verification
Merge remote-tracking branch 'origin/develop' into web_updates

Conflicts:
	MainWindow.cpp