early release of version 5.4.5 (please test)

[Ethan A M. <me...@uw...>]

I have uploaded a testing copy of a version 5.4.5 release to the "testing"
area on SourceForge:
  https://sourceforge.net/projects/gnuplot/files/gnuplot/testing/

The reason for an earlier than usual release is to correct a regression
that affected version 5.4.4 (only) and to provide a fix for mousing in
the Windows qt terminal.

The regression in 5.4.4 caused string->integer type promotion to
incorrectly interpret leading '0' characters as indicating an octal number.
For example in extracting sequence numbers from filenames "run_009.dat",
"run_010.dat", the first conversion would fail ('9' is not a legal octal
character) and the second would yield 8 rather than 10.

My thought is to leave a week for testing and then announce the actual
release at the end of this month.

Changes in 5.4.5
================
* NEW    "set key offset <dx>, <dy>" tweaks placement of the key
* NEW    data-driven histogram colors (variable color from extra using column)
* CHANGE re-order drawing 3D labels to come after pm3d depthorder surfaces
* CHANGE hpgl: add terminal option "fontscale <value>"
* CHANGE for nonuniform matrix data, column(0) returns linear position in matrix
* CHANGE set pointintervalbox 0 disables drawing the background box   Bug #2544
* FIX    svg: hypertext font handling
* FIX    track columnheaders of multiple data blocks in a single file Bug #2538
* FIX    Clean up positioning of polar border, raxis, and theta tics  Bug #2130
* FIX    Autoscaling of logscaled raxis
* FIX    memory corruption if a small plot structure is recycled      Bug #2550
* FIX    regression in 5.4.4 - promotion of string to integer should
         should not assume that a leading 0 means octal               Bug #2551
* FIX    Windows qt: "pause -1" should not block mousing              Bug #2549

        Ethan