show only 10 last signatures and total number of signatures
SignPages: Using islice for the sig list

This will hopefully cause us less hassle in the future if we
every go with a generator based scheme.
SignPages: Not showing the actual signatures by default

The code to show the signatures has not yet been deleted.
You can set SHOW_SIGNATURES to True and it will print the last 10
signatures.  However, I don't like the current design.  It might be
usefuly to have and in fact our "content" is signature, so we should
somehow present those.  But how many and which should be present?  And
what do we offer to do with those?  The user cannot really "remove" the
signatures or edit them in any way, anyway.  So we just do not show the
signatures here, now.
SignPages: Show the signatures label iff SHOW_SIGNATURES is set

We only need this label if we do want to show the list of signatures.
Show only number of signatures, not the signatures themselves

By default, at least.  This fixes a bug which made the widget overly huge
when showing all the signatures on a key.  Then the user couldn't see any button
let alone press ony.