Fixed 1- and 2-argument forms of parse-string-strict.

When called with only 1 or 2 arguments, parse-string-strict deferred its
work to the 4-argument form of parse-string instead of
parse-string-strict (thus still decoding top-level arrays as lazy seqs
instead of vectors).

Finishes fixing #46 and #48.
Merge branch 'pr/51'
Release 5.3.1