The incremented size of `readCycles` better matches the intended number
of tri-cycles the user writes in Rust, since this makes no sense to be
zero-indexed.

Having a lower max debug level for a debug build than a release build makes no
sense. The maximum level for a debug build is now 'trace' (the highest) and for
a release build it is 'info'.

The 'features' of the log module set in the respective Cargo.toml are global.
Adding other features in two Cargo.toml files in the same module gives a
duplicate features error.

Using the log module is slower than the previous method of a global constant
boolean `DEBUG_MODE` with if-statements around `uwrite` calls. Therefore, I had
to increase the values for when to start reading/writing in the switch demo PE
test.

By also returning the DNA, instead of only having it wishbone accessible, we can
also use the device DNA in hardware.