Wharfie

Added example config for the Raspberry Pi RT image.

- some minor fixes in the rpi script (support own kernels, and redo extract of the external zipped image on every run)
- added dbus to the debian base system, as it doesn't work without anymore

Added support for ARM64, w/ an example script for the Raspberry (untested, as I don't have a RPI 3 at hand)

[#7] Support the commands COPY and ENTRYPOINT
- I messed up CMD and ENTRYPOINT

#7 Support the commands COPY and CMD

- fixed rpi bootstrategy
- support kpartx w/ loopback w/o support for sync open

- fixed download in wharfile
- made bs more portable

[#9] Support CODESYS with self-contained raspbian libraries

[#8] experimental implementation of incremental/multi-level build.
Actually it seems as tar has still problems with it. I can't avoid that tar thinks that s.th. is renamed, even if it is not.
In my tests I found no problems, except the warning from tar until now. But I added it as a command line option anyway, to be safe.

By-the-way I fixed the handling of files in ADD a bit.
- URLs are supported now
- Implicite makerules don't interfer anymore with ADD

- cleaned up examples for toolchains
- renamed toolchain examples to a new scheme

enable SPI and I2C on Raspberry Pi by default

added rules for 64 bit support

- moved wpa_supplicant, as this is only an example configuration and has to be adopted by the user

- added options to get system info and to clean intermediate files.
- fixed a small issue in the argument parser, so that you can pass a different filename instead of "Wharfile"

Initial import of Wharfie