Merge 'special_op_handling' into 'trunk'

r6156@Thesaurus (orig r6155):  ribasushi | 2009-05-07 09:28:09 +0200
New branch to allow special op overriding
r6159@Thesaurus (orig r6158):  ribasushi | 2009-05-07 11:55:12 +0200
Allow special op handlers to be a method name alongside a coderef
Switch built-in -in/-between handling to the method calling scheme, to facilitate overriding