Q1) How to enable Emacs keybindings?
R1: Insert 
	gtk-key-theme-name = "Emacs"
    in your ".coqiderc" file. It may be in the current dir
    or in $HOME dir.

Q2) How to change the default font ?
R2) Insert 
	style "default" {
	font_name = "Monospace 14"
	}
	class "GtkTextView" style "default"
    in your .coqiderc file. See Q1.
    You may replace Monospace 14 by anything reasonable describing 
    a font. For example "Sans bold 22". See Pango Font Descriptions for more
    informations (http://www.pango.org/).

Q3) How to enable antialiased fonts?
R3) Set the GDK_USE_XFT variable to 1.