Reveal partially hidden button in "FontInfo / Layers"

On both Ubuntu and Cygwin, when the "Layers" pane of the "Font Info..."
dialog was displayied, the "Delete" button below the "Layers:" list box
was obscured or hidden.

Upon first seeing this, the thought was that the entire "Font Info..."
dialog window would have to be made taller to display the button.
(Another pane "Lookups" would also seem to need this)

Instead, this fix merely shortens the list box, allowing the button to
rise and be seen.  This still allows as many as 8 layer descriptions
to be displayed without scrolling.
1327 version 1. This ports the API over to zeromq 4.0.4 and czmq 2.2.0.
bump the min version during configure as the API for beacons has
changed in the most recent version.
Merge pull request #1579 from monkeyiq/2014/aug/1327

Update to most recent stable zeromq API usage.
Merge pull request #1577 from tshinnic/fontinfo_layers_reveal_button

Reveal partially hidden button in "FontInfo / Layers"
Shuffle code for starting and clearing Python in order to avoid crashes.
Merge pull request #1588 from fontforge/issue_1585_frank_1

Shuffle code for starting and clearing Python in order to avoid crashes.
Add comments regarding tab selection in the Font Info pane.
Merge pull request #1589 from fontforge/anchor_point_fontinfo_destination_fix_1_comments_1

Add comments regarding tab selection in the Font Info pane.