Add message IDs for anything more severe than LOG_DEBUG

This allows easy look-up of the messages from reading logs. We can create wiki pages for each message.

Format:

```
%ANANSI-[INWECA]-0001: Some message or other
```

(letter's correspond to `LOG_xxx` levels)

e.g.

```
%ANANSI-C-0133: Failed to allocate 47 bytes for URI buffer
```
