Add examples/buttons

# feh button configuration.

# Comments start with a # sign, do not use them mid-line.

# Each line must be blank, a comment, or a button definition.

#

# button definition: <action name> <button>

#

# A <button> is a button number with optional modifier.

# For instance, C-1 would be Ctrl + Left click, 4-2 Mod4 + Middle click,

# et cetera.

# Switch menu and zoom keys, useful for two-button touchpads

menu 2

zoom 3