clean sys.argv, because if test is running from pytest
sys.argv contains string "pytest --timeout 0 ./tests/tools"
Beremiz application parses it and throws exception.

rework Beremiz application "testCheckProject" test to allow easier reuse later

add application name for PLCOpenEditor

This is needed to work user configuration load/store, if PLCOpenEditor
is launched from test environment.

rewrite PLCOpenEditor. Add PLCOpenEditorApp class for easier customizations.

lazy locale initialization

wx.Locale() can't be called without wx.App. So don't call it at
import. It makes PLCOpenEditor simpler.

use CustomIntCtrl instead of wx.SpinCtrl because it doesn't support
long integer needed for UDINT, (U)LINT types.

This commit complements commit 74a3f4d "fix LINT and ULINT ranges".