Base functionality improvements

This will be the last release on RetroPie 4.5. Version 4.6 released on April 28th and supports Raspberry Pi 4. It also dropped support for Debian Stretch.

Notable features:

• Cheaper VM (PR #16)
• Copy ROMs script using rsync (see Readme: copy-roms-to-file-share.sh) (f44195c)
• Support scraper credentials (see Readme: add-scraper-credential.sh) (22aef88)
• Environment variables are now in $HOME/.retro-cloud.env and loaded by .bashrc (instead of being inside it) (2650fbe)
• Test script for downloading a freeware ROM and validating that it shows up in the Azure file storage (ab4ef55)
  1. dev/download-freeware-roms.sh
  2. dev/test-az-share.ps1
• Failure management
  • Failed setups no longer requires logging into Azure Portal (see Readme: teardown.sh) (9b921a5)
  • Scripts are chattier, so it's easier to see what failed

Notable fixes:

• Fixed breaking changes in Azure API's (529546c)

See PR's:

• #15 Lint bash scripts with shellcheck
• #16 Min VM for user and Max VM for CI
• #17 Improve development workflow
• Move CI - support mounting VM in Docker container
  • #18 Simplify CircleCI config
  • #19 Simplify CircleCI config further
  • #20 Add TravisCI for validating the mount between VM and RPi