union-1016578: Added union type and unit test
union-1016578: Add polyfill for Array.find

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Fix formatting nits

Also some comment tweaks

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Use correct type store

centralTypes is the default to save implementors creating their own, but
we shouldn't assume the default. The standard way to access the current
types object is to use this.types, which is injected at creation time.
However initially this was restricted to selection/delegate types, however
it didn't make sense to retain this 'special status' so we've opened that
tweak to all types.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: We don't need to store 'lookup' separately

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Use bind rather than self

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: resolve the conversion rather than rejecting it

Nothing has actually broken, it's just that the user typed something
that we can't understand right now, so we resolve with a Status.ERROR
rather than rejecting.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Use 'alternatives' rather than 'types'

Avoids a clash with the parent types object.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Add a getSpec function to the union type

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Add unit tests for getSpec

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Only send INCOMPLETE conversions if none are VALID

Since selection attempts fuzzy matches, it can obscure results that are
valid according to later alternatives. So we ignore incomplete matches
unless there are no valid ones.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
union-1016578: Add unit tests just for the union type

Signed-off-by: Joe Walker <jwalker@mozilla.com>
synchelp-1025017: Fix unit tests for 'help' command

Were broken by recent l10n fixes. This unifies the checks in Firefox
and in Node.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
synchelp-1025017: Remove unused import

Signed-off-by: Joe Walker <jwalker@mozilla.com>
synchelp-1025017: Nit: 'this' doesn't make sense here

Signed-off-by: Joe Walker <jwalker@mozilla.com>
Merge branch 'union-1016578'
Merge branch 'synchelp-1025017'