Improve compatibility with HMG and MINIGUI

[fyurisich]

Improve compatibility with HMG and MINIGUI:

• SET OOP command (non functional). Done. See d30323d
• Error constants. Done. See d30323d
• IsContextMenuDefined. Done. See a0087c2
• IsNotifyMenuDefined. Done. See 7b61599
• Various WM constants. Done. See c43409c
• QUIT command. Done. see 97f7c9b
• LoadTrayIcon function. Done. 2623135
• Control and form context menu. Done. See d30323d
• Control context menu ON/OFF. Done. See d30323d
• Control CLIENTEDGE, STATICEDGE, WINDOWEDGE and NOTEDGE sytles. Done. See fa84e00
• System.x and Sys.x pseudofunctions. Done. See 4810ea8
• NONCLIENTMETRICS. Done. d906882
• CLEAN MEMORY. Done. 26fefa9

[fyurisich]

Also:
SET SCROLLPAGE TO
SET SCROLLSTEP TO
SET AUTOSCROLL ON/OFF
Done, see 5ed05a5

[fyurisich]

Also:
GetMenu
ExistMainMenu
DeleteMainMenu
Done. See ff91179

[fyurisich]

Also:
RELEASE MAIN MENU and RELEASE MAINMENU
RELEASE CONTEXT MENU and RELEASE CONTEXTMENU
RELEASE NOTIFY MENU and RELEASE NOTIFYMENU
RELEASE DROPDOWN MENU BUTTON and RELEASE DROPDOWNMENU OWNERBUTTON
DEFINE CONTROL CONTEXT MENU and DEFINE CONTROL CONTEXTMENU
RELEASE CONTROL CONTEXT MENU and RELEASE CONTROL CONTEXTMENU
Done. See fca6dbb

[fyurisich]

Clipboard related functions. **** PENDING ****
Add HMG´s Random function. Added as HMG_Random. See b9cfef8

[fyurisich]

Remove from compatibility header i_hmg_compat.ch all items related to Minigui and create a new specific header for it.
Done. See 567ea3e