add get_items_at method
gi: extract process
gi: extract Ruby -> GIArgument (interface) process
gi: support GIArgument(interface) -> Ruby conversion
gi: use ALLOC
gi: support SourceFunc callback
gi: accept block
gi: add collection readers to interface
clutter: wrap Threads.add_timeout
clutter: add canvas sample
clutter: wrap Threads.add_idle
gi: guard callback from GC
clutter: Color.new as alias of Color.get_static
clutter: add constraints sample
gi: support Ruby -> GValue conversion
gi: fix wrong function name
clutter: add Clutter::Event::STOP
clutter: use Clutter::Event::STOP
gi: support out parameters
gi: return return value as the first argument of out arguments