assorted problems with error/debug handling

[cpb]

Trying to embed LibECBUFR in various programs can be a bit tricky. First, it has a default "write to stdout" for various kinds of messages. This really sucks if stdout is being used for other things like a web page.

Second, there's no concept of error classification (i.e. warning, error, etc).

[cpb (chris-beauregard)]

The error classification stuff is harder to do since it really requires a whole new output/tracing approach. The "write to stdout" is just a matter of adding output and debug callback handlers (like abort).

[cpb (chris-beauregard)]

Output issues fixed by r165. Error classification logic would be a whole other level of complicated and require revamping just about every message. I'd suggest looking into an external logging/tracing library before tackling that (i.e. nana, libdebug, etc).