gi: add Loader.register_constant_rename_map
gdk3: rename 2BUTTON_PRESS to BUTTON2_PRESS

Because Ruby's constant can't start with a digit.
add initialization with Gdk::RGBA value
this time make it realy work
gdk3 test: Gdk::Event* class initialize takes one argument
Merge pull request #231 from detlefreichl/colorbutton

add initialization with Gdk::RGBA value

Patch by Detlef Reichl. Thanks!!!
gdk3 test: In Gdk Event, #send_event?, #in?, #implicit? and #keyboard? are not defined.

Currently, in Gdk Event, #send_event, #in, #implicit and #keyboard are defined.
These are not Rubyish methods naming....
gdk3 test: Gdk::Window and Gdk::Pixbuf module are not defined.

Currently, Gdk.default_root_window and Gdk.pixbuf_get_from_surface are
defined unexpectedly.
gdk3: define Gdk::Pixbuf singleton_methods
gdk3 test: use Gdk::Pixbuf singleton methods
gdk3: add brank line
vte3-gi: add post_load to require libraries
vte3-gi test: use setup
vte3-gi test: add property test
vte3-gi test: remove unneeded test
vte3-gi test: split test
vte3-gi test: rename test

test_set_font ->
test_font
vte3-gi test: add signal tests
vte3-gi: make private Vte::Loader methods
vte3-gi test: add Vte::Pty test