Change the way the bitlash banner is printed

Previously, the "banner" bitlash builtin and showBanner() bitlash C
function were changed to generate pinoccio-specific output. Now,
Shell.cpp defines a custom "banner" command, keeping the
pinoccio-specific content in pinoccio-specific files. This reverts the
"banner" builtin and showBanner() function, but additionally modifies
showBanner() to use doCommand instead of the execscript directly (since
the original approach only executed the "banner" builtin, without
looking at any functions defined by Shell.cpp.
Remove bitlash code, use an external library instead

The pinoccio version of the bitlash library can be found here:
https://github.com/Pinoccio/library-bitlash
Delete the Lightweight Mesh code

This code is now available in a separate library:
https://github.com/Pinoccio/library-atmel-lwm

Additionally, the code in that library has been slightly cleaned up,
though it should effectively behave the same. One significant change is
that now just uses the millis() timer provided by Arduino, freeing up
hardware timer 4 for other uses.
Convert to a "1.5 style library"

This moves all source into src/ and adds a library.properties file.
Note that this does not really restructure the source yet, there is
still a "src/utility" folder that should be removed next.
Fix include in Backpack.cpp

Now that "utility" is no longer a special folder, it does not appear in
the include path when compiling the library. Thus using
`#include <Backpack.h>` now failed.
Remove js0n code, use an external library instead
Remove Bootstrap example

This sketch also lives in the firmware-pinoccio repository, so this
prevents maintaining duplicate code,
Shuffle all code around

This removes the old utility directory and moves a lot of code from that
directory as well as the root src directory into subdirectories. This
should make the code structure a bit more clear.

This only moves code and updates include paths, nothing is actually changed.