eWiz 0.18.6

Updating eWiz now shows what's happening and comes back on its own

Updates run through Sparkle: "Check for Updates…" (and the Update banner) open a window that checks, shows what's new, downloads with a progress bar, installs, and relaunches the new version — instead of the app quietly quitting and sometimes not reappearing. Checks still happen on launch and daily. One more update goes the old way to get there: this release installs through the previous updater, and every one after it through Sparkle.