[Pharo-project] adding ISO-8859-15 and CP-1252 support

Hi I decided to write ISO-8859-15 and CP-1252 support [1] (mostly for selfish reasons so that Seaside on Pharo would support ISO-8859-15 and CP-1252). A couple of notes: - the five unmapped bytes of CP-1252 (not ISO-8859-15, the comment is wrong) are mapped to the Unicode replacement character (U+FFFD) - a new Latin9 language environment is introduced - some minor clean up like removing unused class variables I'd appreciate it if somebody knowledgeable in these areas could review the changes. I'm especially unsure about the Latin9 language environment, but reusing Latin1 or Unicode seemed wrong. [1] http://code.google.com/p/pharo/issues/detail?id=2812 Cheers Philippe