change reload and service behavior

- Reload service only, if service is running
- Parameter to disable service at boot (required for pacemaker setups)
nfs::export - replaced "substitute" by puppet-native "regsubstr"
Merge pull request #12 from cjeanneret/export-regsubstr

nfs::export - replaced "substitute" by puppet-native "regsubstr"
Merge pull request #6 from saz/enable-service

change reload and service behavior
Update README.rst

fix formatting
Merge pull request #13 from andreas-h/patch-1

Update README.rst
rhel5 and 6 support

Also cleans up a few minor details