[Kst] [Kst-plot/kst] dc7426: Don't crash on crazy time axis values

[Barth Netterfield]

Branch: refs/heads/master
Home: https://github.com/Kst-plot/kst
Commit: dc74268da5114e360136ecd620577751b9d3231e
https://github.com/Kst-plot/kst/commit/dc74268da5114e360136ecd620577751b9d3231e
Author: Barth Netterfield <***@astro.utoronto.ca>
Date: 2016-06-11 (Sat, 11 Jun 2016)

Changed paths:
M src/libkstapp/plotaxis.cpp

Log Message:
-----------
Don't crash on crazy time axis values

Instead just draw a blank axis.
Crazy is defined as t>1E150 years.