remove unused code.xml files

these files were used to validate and parse
code.xml files in catrobatlanguageversion 0.3.
the format is not valid any more
add XStream aliases

* remove package name from xml
* all fields start with lowercase character
remove alias for Look.class

class is not serialized - no XStream alias needed
Merge pull request #190 from Catrobat/CatrobatLanguageVersion0.4

XStream class aliases