Log Message:
Update to 0.054

Upstream changes:
0.054		2018-01-29	T. R. Wyant
    Add support for (+script_run:...). This is an experimental feature
    added in Perl 5.27.8. It imposes on any matches it contains the
    additional restriction that everything matched has to belong to the
    same Unicode script. This support will be retracted if the
    functionality does not make it into Perl 5.28.

    Add method scontent().  This returns significant content only. That
    is, if called on the parse of '/ f u b a r /x', it returns
    '/fubar/x'.