Custom fonts and other design improvements

[Andrea Colombo]

Hey, congrats for the job you did on the app.

I forked the repo and implemented a few design improvements, you can check the screenshots and you can install the apk to try it yourself.

I implemented custom fonts, twotone icons and I made the logbook scroll, cause it seemed weird to me that it only occupied half of the screen. Also I cleaned up some parts of the code. I also created a logo for the app and changed the icon.

All of the changes I made for myself to use the app, so I completely understand if you don't like all of them, or any. If you'd like tho, I could open targeted pull request (let's say, logbook only, fonts only, icons only, etc.) so lmk.

Posting the screenshots here as well just for reference.