use vibe.core.log when Have_vibe_d_core

[SingingBush]

when mysql-native is being used in a vibe-d application it may be handy to make use of vibe-d's logging.

I'm currently seeing some problems when my application attempts to load some data from mariadb so I decided to increase the logging. I can see plenty from both my app and vibe-d but nothing from mysql-native.

It would be really handy if you guys were making use of logDebug, logInfo and logError

[s-ludwig]

The ideal solution would probably be to use std.experimental.logger and plug that into vibe.d's log system. The main issue with this is that std.experimental.logger has no semantics defined for log levels < "info". It only has trace, with a number of unassigned integers to the nest level info, so mapping this to vibe.d is quite ambiguous.

[SingingBush]

That's also fine with me. (I created vibe-d issue 1530 for making use of std.experimental.logger)

It's unfortunate that it doesn't have a log level for debug, I've raised it on the phobos issue tracker

[schveiguy]

Closed in #187