[Cake] allocate_src allocate_dst

[Kevin Darbyshire-Bryant]

> On 25 Nov 2017, at 16:41, Jonathan Morton <chromatix99 at gmail.com> wrote:
> 
> Not quite.  The "dual" enums have more than one bit set, so you have to test them for equality.
> 
> - Jonathan Morton

Here you go https://github.com/ldir-EDB0/sch_cake/commit/795db1d1df9f9a400d8c4861eeff59b85994ccfb  - rebased onto current cobalt.

Compiles, have built firmware… internet in use so still not actually run.

(KDB secretly likes the gotos )