[Ohrrpgce] SVN: teeemcee/9455 Ignore repeated calls to showerror with the same message, after the seco

[subversion at HamsterRepublic.com]

teeemcee
2017-09-24 22:45:54 -0700 (Sun, 24 Sep 2017)
227
Ignore repeated calls to showerror with the same message, after the second call

It would be good to do the same for all debug, debugc, visible_debug,
and notification calls. Unfortunately, our error displaying is a total mess.
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U   wip/common.rbas