Set SSLOptions StdEnvVars in server context

We set `SSLOptions` now in server context and we set it to `StdEnvVars`.
Thus, we no longer need the <FilesMatch > in server context to set it
for php, CGI and SSI applications.
We allow it to be overridden by the `apache::mod::ssl` class parameter
`ssl_options`. Further, we allow it to be overridden in directory
context.
Documentation for all of these has been extended and tests have been
adapted to make sense in this new context. This commit fixes #487
Merge pull request #490 from igalic/global-sslopts

Set SSLOptions StdEnvVars in server context
Add suPHP_UserGroup directive to directory context

suPHP_UserGroup is only supported in per-direcctory context. We add this
directive analogous to the per-vhost suphp_ directives, by making sure
that suphp_engine is actually enabled.

  suphp => { 'user' => 'myappuser', 'group' => 'myappgroup' }

With documentation and tests in place, this should fix #451
Merge pull request #497 from igalic/suphp_usergroup

Add suPHP_UserGroup directive to directory context