Ldapper v0.4.0

Which build you are running is now on screen, and the README shows what
Ldapper looks like.

The version, where you will look for it

Bottom right of the status bar. It is the one place always on screen, it is
the first thing a bug report needs, and a separate About window for a tool
this size is a click nobody wants.

A build made without the stamp says dev rather than claiming a release it is
not, and a build from a working tree with uncommitted changes gets a +. The
tooltip carries the commit.

Screenshots

The README now shows browsing, searching, the filter library and the
connection dialog.

Two more fixes, found while taking them

• The heading above the attribute table showed Volkova\2C Anna. The
  unescaping added for the tree had never been applied there, so the two panes
  disagreed about the same name.
• Double-clicking a tree row to expand it also selected the label and started
  a drag, which made the row look like it had come loose.
• The scope selector wrapped "One level" onto two lines, making that segment
  taller than the ones beside it.

For anyone working on the interface

npm run dev in frontend/ now runs the interface against a stand-in for the
Go side, so it can be worked on without building the application. It is the
same components and the same stylesheets — it is how the screenshots above
were taken.

Verified

318 Go tests, 46 frontend tests, 37 integration tests.