fix test failures due to assumptions on pairs() ordering

Update the tablex spec to sort the results of tablex.keys() and
.values() before testing them, to ensure consistency.
Merge branch 'fix-spec-sort-pairs'
fix typo which prevents detection of Windows

(I think... maybe someday someone will care enough to haul out a Windows
box to test this.  But today is not that day for me.)
revert previous, fix it the other way around

is_windows is public, so shouldn't be underscored
add tests for computercraft based on os.version

also add defaults for dirsep/pathsep, as CC lacks
the "package" standard library
Merge branch 'fix-win-test'
Merge branch 'port-to-computercraft'