Don't exit select mode when panning selected feature out of view
Return false when checking selected IDs and switching between single and multiselect in modeSelect
What could happen was:
- user could right click on a line
- this would trigger `disabled()` checks for each operation buttons
- the line was not fully downloaded, so would return `disabled()` 'not_downloaded'
(and also start download of the missing tiles)
- then the tooltip would pop into existence, calling `tooltip()`
- which calls `disabled()` again
- but this time it's fine and the `disabled()` is false
- so you'd see a greyed out button but the tooltip said everyting is ok and
you can click the button anyway
I fixed this by just caching the disabled test. This is probably ok anyway
because these tests can be expensive, and then the user will see a consistent
message like "The line is not yet fully downloaded".
If the user clicks off the line and back onto it, iD will reenter select mode,
rebuild the menu, redo the disabled test, and they will see the button enabled.
(closes#4841)
Before, first/last keyboard shortcuts only worked if you had a vertex selected.
Now you can navigate to the first/last vertices even if you have the way selected.
(re: #3003 / #4602)
For now, drawHover is commented out. Still not sure what I will do with it.
This means that things flicker a bit when dragging, also connecting nodes
(and closing lines) does not currently work.
There was lot going on preventing the vertices from rendering while dragging.
1. `modeDragNode` needed a proper `selectedIDs()` function that works like other
modes.. Many other places in iD (including the vertex renderer) call `context.selectedIDs()`..
This means that `modeDragNode` needs a new function `restoreSelectedIDs()` to do what
`selectedIDs()` was previously doing (a place to store selectedIDs so that we
can reselect those entities after the user is done dragging a node in select mode)
2. Just so many things in svg/vertices.js
- siblingAndChildVertices was missing some things for points that we render
as vertices (points in wireframe, points with directions)
- the sibling vertices weren't being included in the `filter` function, so
would disappear when doing differenced/extent redraws
- probably some other things
