Command to display the script's version about flash

[StefanScherer]

@jmMeessen Great idea.
I'll remove the -v option from the --verbose and display the version instead.

I thought how to maintain that version string in both scripts, and still support pull requests from the community.

• For these bash scripts we will go with a GitHub release that inserts the version into both scripts.
• In the source code there will a version number like "dirty".
• We have to update the installation steps to download it from the GitHub release page instead directly from source tree.

[StefanScherer]

As we now have a small CI pipeline on Circle + Travis we could think of automating this and make releases with version numbers ;-)

[StefanScherer]

Finally, you can run flash --version.

Download latest release with

curl -LO https://github.com/hypriot/flash/releases/download/2.1.0/flash
chmod +x flash
sudo mv flash /usr/local/bin/flash