(QE-90)  validate test systems have required packages/services before
testing.  First pass -  checks for curl and ntpdate, installs if missing
move install_package and check_for_package into appropriate host
platform code
supports windows and unix - not solaris + aix
windows installs cygwin packages, cannot install 3rd party cygwin
packages (like ntpdate)
Merge pull request #499 from anodelman/validator

(QE-90)  validate test systems have required packages/services before testing