Add support for parallels provider and use NFS for shared filesystem.

[rterbush]

[nsh87]

I think some more ifs are needed in Vagrantfile to conditionally support NFS and Parallels. Hopefully this is helpful: I don't have Parallels or any NFS shares mounted and on vagrant up I get about a 35 minute hang after the VM boots.

==> default: Machine booted and ready!
==> default: Checking for guest additions in VM...
==> default: Configuring and enabling network interfaces...
==> default: Exporting NFS shared folders...
==> default: Preparing to edit /etc/exports. Administrator privileges will be required...
Password:
==> default: Mounting NFS shared folders...

Then the error:

The following SSH command responded with a non-zero exit status.
Vagrant assumes that this means the command failed!

mount -o 'vers=3,udp' 192.168.33.1:'/Users/Nikhil/dev/shinyVM/project' /www-shiny

Stdout from the command:

Stderr from the command:

stdin: is not a tty
mount.nfs: Connection timed out