[Devel] standardized log messsage formats

[Juha Heinanen]

looks like each module has invented its own format (or even uses many
different formats) for error and debug messages.  this includes modules
that i have written myself.

imo we should standardize the formats.  i don't have any strong opinion
how they should look like, but below is a suggestion:

debug messages:

DEBUG:module:function: debug-message-itself

error messages:

ERROR:module:function: error-message-itself

comments and better suggestions for formats are welcome.

-- juha