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
add Puppet future parser to Travis matrix

Only Puppet 3.5 for now; rspec-puppet doesn't work with anything higher.
Allow failures since future parser is still pre-release.
bug fixes surfaced by future parser

* concat::fragment requires 'order' to be a string
* init parameters added in #373 referred to wrong variable name in params.pp
* bug fixed in test suite