[distcc] updating manpages

[Martin Pool]

I've have just gone through and updated the manual to clarify some
sections and remove old information.  In the process I have merged the
information into the manpages and will be removing the Linuxdoc manual
from the distribution.  

I hope this will make the information more acccessible and reduce the
heinous problems of building SGML on different distributions or
systems.

Review comments would be welcome.

-- 
Martin