Add oUnit to merlin package list
Correct tests for empty queries and add tests for with_* change functions
Fix empty-but-existing query ('?') parsing bug
Fix with_userinfo against hostless URI representation bug
Fix with_port against hostless URI representation bug
Fix with_path with relative path against hosted URI representation bug

Fixes #51.
Fix make representation bugs

without host but with userinfo or port creates an empty host
with host, userinfo, or port and with a relative path makes the path absolute but does not otherwise resolve it
Update version to prepare 1.7.2, give maintainership to @dsheets
OASIS regen
Clearer empty query string handling (thanks @avsm)
Merge pull request #52 from dsheets/with_change_fixes

with_* fixes