Add information about the log message generation location to wxLog.

Add information about the log message generation location to wxLog.

This means that wxLog::DoLogRecord() can now retrieve the file name, line
number and the function where the message was logged.

An unfortunate consequence of this change is that now

	if ( condition )
		wxLogError("Whatever");

results in a warning from g++ 4.x with -Wparentehses, so extra parentheses had
to be added in many places.

Finally, also allow storing arbitrary attributes in wxLogRecordInfo. This had
to be added to implement our own overloaded wxLogStatus() and wxLogSysError()
and will probably be useful for the others as well.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61363 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775