Eliminate wire-strings for user-defined patches

[dpwe]

Currently, user-defined patches are stored either as wire strings (via char *memory_patch[patch_number]) or as lists of deltas (via struct delta *memory_patch_deltas[patch_number]). In patches_load_patch, the deltas list is used if present, otherwise the wire string is used.

We got here historically: First, there was only wire strings, then we added delta lists to allow patches to be defined without using wire string syntax, but we were (and still are) using wire-string definitions in a few places (like setting up default synths in api.c).

It's confusing to have these two levels. I think we can successfully remove the wire-string storage/support.

Note that the built-in patches (Juno, DX7) will continue to be defined as wire strings in patches.h. Currently, get_events_for_patch_number, which exists purely to configure the web editor parameters, works from these wire strings. I'd like to make it also work for user-defined patches, but that will need a new mechanism to reconstruct events from a list of deltas. This will be a little weird, since each delta describes a single non-default value within an amy_event structure. The constraint is that each delta specifies an osc, and a single amy_event can only have a single osc value. I think I can write a deltas_queue_to_amy_events that works well enough to support this.