Add prevent_upgrade option

[esalberg]

• add prevent_upgrade option (does not deploy files if the Puppet version is higher than the installed version)
• rewrite logic around prevent_downgrade to include prevent_upgrade
• modify the regex for how to download vmwaretools to fix a Lint issue with the previous syntax

I did the following manual functional testing (PE 3.3.2, RHEL 6.5 only, puppet:/// file source): vmwaretools version increase, both prevents set to true goal: no upgrade actual: no upgrade

vmwaretools same version, both prevents set to false goal: no upgrade actual: no upgrade

vmwaretools version increase, prevent_upgrade set to true (prevent_downgrade set to true) goal: no upgrade actual: no upgrade

vmwaretools version increase, prevent_upgrade set to false (prevent_downgrade set to false) goal: upgrade (install) actual: upgrade (install)

vmwaretools version decrease, prevent_downgrade set to true (prevent_upgrade set to false) goal: no downgrade actual: no downgrade

vmwaretools version decrease, prevent_downgrade set to false (prevent_upgrade set to true goal: downgrade actual: downgrade

no vmwaretools installed, prevent_downgrade and prevent_upgrade set to true goal: install actual: install