Review: std.logger

[Robert burner Schadek via Digitalmars-d]

I just pushed a new version to dub and the PR.

Highlights:

* LogManager is gone. ( s/LogManager\.//g should fix all user 
code)
* The codegen was replaced by some format token strings
* log(lcf) and trace(cf) now present documentation
   * trace(cf) stands as an example for info, warning ... and so 
forth
* StdIOLogger is now thread safe
* StdIOLogger docu tells you that it is thread safe

I also updated the html documents so you don't have to read 
through the source, but you are of course welcome to do so.