connection: Rename wl_buffer
struct wl_buffer has other meaning in wayland, thus making this a pretty confusing structure name. Function names like wl_buffer_put() just compound the confusion.
Blindly rename the struct and the associated functions (none of which are called from outside this file anyway).
I've fairly arbitrarily picked "con_buffer" as shorthand for connection buffer.
Signed-off-by: Derek Foreman derek.foreman@collabora.com