Work toward making inspector persistent
Use undefined value to remove a key rather than empty string

Otherwise it is impossible to tab out of the key input of a
new tag row -- since the value is still empty, the tag is
removed before you have a chance to enter a value.
Add hover indicator in sidebar
minor adjustments to sidebar, adding mock-ups.
work on hover state.
Remove hacky overrides
Fix preset form field spacing
Rationalize CSS classes
Fix taginfo caching
Don't show "Editing" on hover
Transitions
Clear sidebar when not hovering (fixes #1528)
Fix Name field's + button (fixes #1529)
Make preset field placeholders translatable
Fix field placeholders
Fix tests
working on hover styles.
Merge branch 'sidebar' of github.com:systemed/iD into sidebar
adding placeholder text and exception for showing placeholder on radio buttons during hover.
Ensure combobox suggestion menu is closed on blur

The combobox's blur handler needs to be called prior
to the tag editor's blur handler. The latter can cause
a re-render, which will rebind handlers. Rebound handlers
are not called during the same event dispatch cycle, so
when the combobox blur handler is last, it sometimes
doesn't get called, stranding the menu.