3.8.0 - Bug fixes. Tweak to JTBeta file detection

Fixed a couple small bugs. The app will exit after running update, like it used to.
If the extracted jtbeta bin is found on the root of your sd card, the updater will use that for

What's Changed

• Bugfixes by @mattpannella in #269
• check for beta.bin as well as jtbeta.zip by @mattpannella in #270
• minor version bump by @mattpannella in #271

Full Changelog: 3.7.1...3.8.0