Gerbview crashes on start (lp:#1763270)

[Original report](https://bugs.launchpad.net/bugs/1763270) created by **Martin Thomas (mtlaunchpad)**
```
Since the End of last week Gerbview crashes for some reason.

I am using the current Version (git has
86f744a1fd554c0a98e77724fd41b1472b2fca6f).
Version 5.0.0-rc2-dev-416-g86f744a

Kubuntu 16.04
Kernel 4.14.33
Core(TM) i5-7400



(gdb) start
Temporary breakpoint 1 at 0x44351a: file
/home/mthomas/daten/git/kicad/kicad-source-mirror/common/single_top.cpp,
line 239.
Starting program: /usr/local/bin/gerbview
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Temporary breakpoint 1, main (argc=1, argv=0x7fffffffddf8) at
/home/mthomas/daten/git/kicad/kicad-source-mirror/common/single_top.cpp:239
239     IMPLEMENT_APP( APP_SINGLE_TOP )
(gdb) cont
Continuing.
gerbview: /home/mthomas/daten/git/kicad/kicad-source-
mirror/common/tool/action_manager.cpp:223: void
ACTION_MANAGER::UpdateHotKeys(): Assertion `global_actions_cnt <= 1'
failed.

Program received signal SIGABRT, Aborted.
0x00007ffff5ab8428 in __GI_raise (sig=sig@entry=6) at
../sysdeps/unix/sysv/linux/raise.c:54
54      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) bt
#0  0x00007ffff5ab8428 in __GI_raise (sig=sig@entry=6) at
../sysdeps/unix/sysv/linux/raise.c:54
#1  0x00007ffff5aba02a in __GI_abort () at abort.c:89
#2  0x00007ffff5ab0bd7 in __assert_fail_base (fmt=<optimized out>,
assertion=assertion@entry=0x7fffece56cba "global_actions_cnt <= 1",
    file=file@entry=0x7fffece56bd0 "/home/mthomas/daten/git/kicad/kicad-
source-mirror/common/tool/action_manager.cpp", line=line@entry=223,
    function=function@entry=0x7fffece56da0
<ACTION_MANAGER::UpdateHotKeys()::__PRETTY_FUNCTION__> "void
ACTION_MANAGER::UpdateHotKeys()") at assert.c:92
#3  0x00007ffff5ab0c82 in __GI___assert_fail (assertion=0x7fffece56cba
"global_actions_cnt <= 1",
    file=0x7fffece56bd0 "/home/mthomas/daten/git/kicad/kicad-source-
mirror/common/tool/action_manager.cpp", line=223,
    function=0x7fffece56da0
<ACTION_MANAGER::UpdateHotKeys()::__PRETTY_FUNCTION__> "void
ACTION_MANAGER::UpdateHotKeys()") at assert.c:101
#4  0x00007fffecd97bf5 in ACTION_MANAGER::UpdateHotKeys (this=0x3d12a90) at
/home/mthomas/daten/git/kicad/kicad-source-
mirror/common/tool/action_manager.cpp:223
#5  0x00007fffecd250a5 in TOOL_MANAGER::SetEnvironment (this=0x3d27b00,
aModel=0x3210560, aView=0x31dd8f0, aViewControls=0x320fac0,
aFrame=0x1c6ba50)
    at /home/mthomas/daten/git/kicad/kicad-source-
mirror/common/tool/tool_manager.cpp:853
#6  0x00007fffecc060e2 in GERBVIEW_FRAME::setupTools (this=0x1c6ba50) at
/home/mthomas/daten/git/kicad/kicad-source-
mirror/gerbview/gerbview_frame.cpp:1254
#7  0x00007fffecc00c2b in GERBVIEW_FRAME::GERBVIEW_FRAME (this=0x1c6ba50,
aKiway=0x6dc300 <Kiway>, aParent=0x0)
    at /home/mthomas/daten/git/kicad/kicad-source-
mirror/gerbview/gerbview_frame.cpp:206
#8  0x00007fffecbc0414 in GERBV::IFACE::CreateWindow (this=0x7fffed4f0380
<GERBV::kiface>, aParent=0x0, aClassId=14, aKiway=0x6dc300 <Kiway>,
aCtlBits=1)
    at /home/mthomas/daten/git/kicad/kicad-source-
mirror/gerbview/gerbview.cpp:70
#9  0x000000000047334d in KIWAY::Player (this=0x6dc300 <Kiway>,
aFrameType=FRAME_GERBER, doCreate=true, aParent=0x0)
    at /home/mthomas/daten/git/kicad/kicad-source-
mirror/common/kiway.cpp:335
#10 0x0000000000443ace in PGM_SINGLE_TOP::OnPgmInit (this=0x6dc720
<program>) at /home/mthomas/daten/git/kicad/kicad-source-
mirror/common/single_top.cpp:322
#11 0x00000000004473fa in APP_SINGLE_TOP::OnInit (this=0x73f620) at
/home/mthomas/daten/git/kicad/kicad-source-mirror/common/single_top.cpp:128
#12 0x0000000000445cc1 in wxAppConsoleBase::CallOnInit (this=0x73f620) at
/usr/include/wx-3.0/wx/app.h:93
#13 0x00007ffff69fef92 in wxEntry(int&, wchar_t**) () from
/usr/lib/x86_64-linux-gnu/libwx_baseu-3.0.so.0
#14 0x000000000044352d in main (argc=1, argv=0x7fffffffddf8) at
/home/mthomas/daten/git/kicad/kicad-source-mirror/common/single_top.cpp:239
(gdb)
```

Story points: 6.0