refactoring: introducing enums

compiling but not running !!!
refactoring dictionary as enum & enumMap
refactoring: Tags as enums

compiling, but throws exceptions!!
fix xml: tags should be lowercase
fix equals: should compare strings
bugfix refactoring
bugfix parsing: ignore unknown tag and print warning
refactoring: etype as enum

compiles, but throws exceptions!
remove menu_scanning entry from xml
refactoring: codes
refactoring: remove ITag, debugging
bugfix: types and codes
refactoring: statuslistener unsing enumeration of status instead of propertyChangeListener
fixes: init units, menu handler
refactoring: action keys should be strings
bugfixing: tags, capitaliation, casting
refactoring: Descriptor keys as enum
refactoring descriptor
refactoring skin tags in tags & attributes
supress ignore warning for eniac tag