Use current user's uid for NFS exports
Merge branch 'nfs-per-user' of https://github.com/davedevelopment/vagrant into davedevelopment-nfs-per-user

Conflicts:
	plugins/hosts/arch/host.rb
	plugins/hosts/bsd/host.rb
	plugins/hosts/linux/host.rb
	templates/nfs/exports.erb
	templates/nfs/exports_freebsd.erb
	templates/nfs/exports_linux.erb