Correct validation of {proxy,fastcgi}_cache_levels

Allow any combination of 1 and 2 in these formats: X, X:X,
and X:X:X, e.g.: "2", "2:2", "1:1:2". The old validation failed if
it wasn't an integer which didn't allow these formats.
bump puppet-lint version to 1.0.1

Required for .puppet-lint.rc and puppet-lint control comments
Merge pull request #382 from 3flex/294-fix-proxy_cache_levels-validation

Correct validation of {proxy,fastcgi}_cache_levels
Removed proxy_cache_valid as default when using proxy_cache option
Added some tests also
Merge pull request #434 from pablokbs/proxy_cache_valid_fix

Removed proxy_cache_valid as default when using proxy_cache option