Bugfix release: false positives for UnusedUseStatement linter

This release fixes a bug in the UnusedUseStatement linter for use type and use statements:

<?hh // strict

// earlier versions of HHAST would incorrectly report `GenericParent` as unused
use type Foo\GenericParent;

class Foo<T> extends GenericParent<T> {
}

This release also includes more complete CSS for the hhast-inspect developer tool.