Allow apache::mod to specify module id and path

Add $id, $path and $lib_path parameters to apache::mod. These parameters
are used in #342. The purpose of the whole thing is to plit #342 into
smaller parts to make review process easier, see
https://github.com/puppetlabs/puppetlabs-apache/pull/342#issuecomment-25423813

This PR covers all changes introduced by #271 to manifests/mod.pp. I
just don't have test/mod_load_params.pp as in #271.
Add new params to apache::mod::mime class

This changeset adds $mime_support_package and $mime_types_config
parameters to class `apache::mod::mime`. Their purpose is following:

- $mime_support_package - install this package, as it provides mime.conf
  file (definition of mime types used by mod_mime),
- $mime_types_config - used to substitute TypesConfig in
  mod/mime.conf.erb template.

This PR was created in order to plit #342 into smaller
parts to make review process easier, see
https://github.com/puppetlabs/puppetlabs-apache/pull/342#issuecomment-25423813
Merge pull request #445 from ptomulik/explicit_mod_id

Allow apache::mod to specify module id and path
Merge pull request #447 from ptomulik/mod_mime_params

Add new params to apache::mod::mime class