Update of the CB user manual

[Jenna]

Hi Jens,

we should add also the chm version of the manual and index.ini file in the directory share/codeblocks/docs, then the manual entry will be displayed in the help of Code::Blocks and it becomes more obvious for the users. Since some chm viewer exist under Linux I think this would be reasonable.

There are several chm-viewers, but they are not installed by default.
I would prefer to do use a plain html file (or better structure) on linux together with the integrated html-viewer (if that works) or the standard-browser, because chm's are normally native windows files.

And I would also prefer to keep documentation below /usr/share/doc/, because that's the place it belongs to.
It would work, if absolute-paths can beed in index.ini.
I will see if this can be done, if I have some more time.