Created ParameterTrait::isVariadic(), and wrote tests (depends on #158 being fixed).
Er...as far as I can tell, the isVariadic tests are passing.
Explicitly added PHP 5.6 requirement to the isVariadic() test.
Improved support for variadic functions
Renamed EllipisNode to SplatNode
Merge pull request #168 from grom358/is_variadic

ParameterTrait::isVariadic()