[Cdash] doxygen -> documentation

[Igor Murzov]

What about help messages for `username` and `password` fields
on repository settings page? For example, the help message for
`username` says:

 "Optional. Provide a username if you do not wish to use
  anonymous SVN access."

I don't use SVN, I use Git, and such description looks confusing
to me. For instance, it's not obvious, if I should write
 
 Repository: git at server.com:project.git

or

 Repository: server.com:project.git
 Username: git

because the description of the `username` field doesn't mention
any VCS other than SVN. I think these messages could be clarified.


Actually, I would like to have a per project setting called
`VCS type`, not only `Repository`, `Repository Viewer URL` and
`Repository Viewer Type`, because guessing repository type
from repository viewer type doesn't work well. At least getting
daily updates doesn't work for me. My VCS is Git and repository
viewer is Redmine, but CDash will identify a VCS as Git, only
if its repository viewer is one of: `gitweb`, `gitorious` or
`github` (line 669 of cdash/dailyupdates.php).


-- Igor