Changed wxLog DoLogXXX() callbacks and introduced wxLogRecordInfo.

Changed wxLog DoLogXXX() callbacks and introduced wxLogRecordInfo.

The main logging callback is now DoLogRecord() with DoLogTextAtLevel() and
DoLogText() provided for convenience. The old DoLog() and DoLogString() are
still called but deprecated and their overloads taking wxString which were
only added in 2.9.0 are removed.

wxLogRecordInfo allows associating more information than just the time stamp
with the log record; for now only the logging thread id was added but more
fields will make their appearance soon.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61346 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775