Update to gerbv-2.5.0

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Release Notes for gerbv-2.5.0
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The following is a summary of the changes which went into gerbv-2.5.0.
For a complete list of changes, refer to ChangeLog.  This release
is primarily a bug fix release.

- libgerbv:  fix leak and possible segfault in drill parser
- libgerbv:  fix segfault in pick and place parser
- gerbv:    add persistent keyboard accelerators and extra menu options
- gerbv:    increase max zoom 4x to allow more accurate measurements
- libgerbv:  fix bug which caused the drill parser to crash on an empty line
- gerbv:    change F8 shortcut to F7 per GNOME HIG
- gerbv:    add psuedo fullscreen mode
- gerbv:    add ability to toggle sidebar visibility
- gerbv:    speed up cairo rendering.
- libgerbv:  improved detection of drill files (comment lines are now
            ignored during file type detection)
- libgerbv:  fix handling of trailing zero suppression with very large
            precisions.
- examples:  fix some of the example code showing how to use libgerbv.
- gerbv:    fix gdk rendering of macro 22 elements with negative coordinates
- gerbv:    fix tooltip for modify layer button
- libgerbv:  fix handling of whitespace in the middle of an RS-274X command
- libgerbv:  fix bug in exporting outline macros
- gerbv:    unselect all items if a layer is hidden
- libgerbv:  fix drill parsing when INCH has nothing after it

(dmcmahill)