Make orxonox.log configurable

[rgrieder]

Creating the Orxonox log is about the first thing that our program does after execution. That implicates that at that moment it is not yet known where to write the log data. The resolution is to always write everything to "orxonox.log" in the current working directory.
But this concept doesn't hold with binary distribution. I suggest making a little workaround: Do not write output until the output file path is known (that is before the GameStates are created) but instead cache it in a buffer.
The obvious problem is of course that when an error happens before that, there is no output to examine. This could be resolved by implementing a fallback that can be switched on (maybe with a macro) in OutputHandler.cc

[rgrieder]

orxonox.log gets written to the log directory per definition (hard coded) now. But since that directory can be compile time (also install vs. development run) variable, all output is written to tmp/orxonox.log (Unix) or %TEMP%/orxonox.log (Windows) and then copied to the right logfile once the folder is known (after main()).