Implemented log viewer dialog for the wx gui
- added new class LogViewDialog based on the already removed DebugLogDialog
- log output is only sent to the viewer if visible to avoid performance trouble
- text buffer is limited to 48k, older lines are removed if necessary
- red text color is used for error and panic messages and black for others
- minor related code cleanups


git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12108 6c8e4198-a580-4521-a02f-c9ae86df1db9