SEALS v0.3

This release:

• New 'PC' platform (x86_64 / amd64) supported. (This is the QEMU-emulated 'Standard PC (i440FX + PIIX, 1996) (alias of pc-i440fx-7.2)')
• Test / Q&A:
  There's now a test/ folder with:
  • a shellcheck_run script
  • all board config files configured to turn on all menu options (& thus test close to everything while building the target platform)
• several tweaks & bug fixes
• a quite detailed Tutorial showing newbies how to use SEALS (with many screenshots thrown in).

SEALS v0.2

This release incorporates numerous features and bug fixes. Key ones are:

• supports both Aarch32 and Aarch64 Qemu-emulated target systems!
• the default build.config is a soft link to an Aarch64 configured 'dummy-virt' ARM64 Linux box
• a new installer interactive script (install.sh) auto-installs the busybox + kernel source trees
• enhanced Wiki documentation on toolchain install (https://github.com/kaiwan/seals/wiki/SEALs-HOWTO)
• the run-qemu.sh script is also invoked via the build system
• better / restructured layout for the build.config config file
• robust scripts by using unofficial Bash 'strict mode' throughout