Add test-like statement to dumb test
Start implementing SignalBuilder
Map arguments and return value in signal mapper
Extract mapping method building to a class
Use MappingMethodBuilder from CallbackBuilder also
Extract helper methods for mapping method definition
Refactor MappingMethodBuilder#method_definition
Move module and class definers to BuilderHelper
Enable creation of safe names for signal handler modules

- Make #safe_name available to ISignalInfo
- Make #safe_name handle names with dashes
Pass only needed information to MappingMethodBuilder

This will allow manipulation of the passed-in argument type infos later.
Handle signal receiver and user data in generated signal argument mappers
Handle enum arguments to callbacks in mapping methods
Make SignalBuilder build signal modules under the parent class
Use generated signal argument mappers to handle signals
Clean up unused methods