minimal changes (6): deprecated part ; missing check at layout opensuse ; keep history-last-run ; active compiz was not detected ; check Layout saved ; check exists before remove

[2387skju]

6 (mostly) unimportant changes:

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1.) Deprecated gtk parameter updated:
Update to GTK Parameters, to remove these deprecated warnings:

/usr/bin/mate-tweak:684: PyGTKDeprecationWarning: The "buttons" argument must be a Gtk.buttons enum value. Please use the "add_buttons" method for adding buttons. See: https://wiki.gnome.org/PyGObject/InitializerDeprecations
  dialog = Gtk.Dialog(title, None, Gtk.DialogFlags.MODAL | Gtk.DialogFlags.DESTROY_WITH_PARENT,
/usr/bin/mate-tweak:684: PyGTKDeprecationWarning: The "flags" argument for dialog construction is deprecated. Please use initializer keywords: modal=True and/or destroy_with_parent=True. See: https://wiki.gnome.org/PyGObject/InitializerDeprecations
  dialog = Gtk.Dialog(title, None, Gtk.DialogFlags.MODAL | Gtk.DialogFlags.DESTROY_WITH_PARENT,
/usr/bin/mate-tweak:690: PyGTKDeprecationWarning: Using positional arguments with the GObject constructor has been deprecated. Please specify keyword(s) for "label" or use a class specific constructor. See: https://wiki.gnome.org/PyGObject/InitializerDeprecations
  label = Gtk.Label(text)

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2.) For layout Opensuse is mate-menu required:
It has MateMenuAppletFactory::MateMenuApplet (see in layout-file Opensuse).
Problem results in: I don't see there any Menu at Debian, without installing that package.
Suggest: Distributions should add mate-menu as suggested package (for mate-tweak).

This is an re-opened of an already closed pull Request (i realized afterwards):
"add mate_menu dependency on opensuse layout": #72

flexiondotorg wrote: "The opensuse layout is legacy, and not dependaent on MATE Menu."

But, I thinks this was wrongly closed.

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3.) Keep history-last-run:

This keeps the current run program history of the user, while changing the Panel.

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4.) Active compiz was not detected

Active Windowmanager compiz was not correct detected, after opening Mate-Tweak once again: The Buttons for Reset and CCSM was missing and red text ".. unknown and unsupported windowmanager. ...".
Problem is: variable current_wm='compiz', but is checked for 'Compiz' (initial letter different).
I changed the code, to be not case-sensitive anymore.

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5.) Check Layout saved / deleted
If layout was not saved or deleted, stop continue.
Use-Case: That could happened, if pkexec failed: The distribution opensuse does not include the policy-file, therefore it will ask for password. The User could cancel (or fail) that password request.

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6.) check exist before remove a system-wide autostart
Check if the autostart file exists, before remove them ( = calling pkexec mate_tweak_helper autostop ... ).
This will result in less actions with Root-Right.
Use-Case: The distribution opensuse does not ship the policy-file (= So, every root-request a needs password ).