Extended class functionalities

- class_type(t) now extends type() returning original type if the
parameter is not a class.
- is_a(t)
- implements(t)
- super(t)
use of new class_type
Extended Callbacks functionalities

- support of parameters in callback definition. if a registered
callback is a function / method accepting parameters, it’s now possible
to provide them either at creation or at call time
- is_function(t) check if function or callback
IAnimatable object must implement advanceTime
table.extend

table.extend(t1,t2) allows to extend t1 with the content of t2
Added split functions for bitfields

split mask and split bits allows to split a bitfield into 2 bitfields
(high / low part)
getPointerPosition

added tracking mouse position, mainly for debug purposes
Color improvements & Named colors

- added a set of named colors under Color ‘namespace’
- operations now works also on alpha (break compatibility)
- hex string to color conversion
- normalization logic
Stage set/get BackgroundColor

- Stage:setBackground renamed to setBackgroundColor
- Added getBackgroundColor