* TypeMap: prepare refactoring into a modular design
* TypeMap: refactor C++ backend into common methods
* TypeMap: refactor CLI backend into common methods
* CLI.Gen.cs: fix omitted typemap from previous commit
* Common.Gen.cs: fixed silly modification while testing
* GeneratorKind: add FindGeneratorKindByID method
* TypeMapDatabase: heavy refactor: group typemaps by GeneratorKind
* TypeMap: refactor CSharp backend into common methods + migration
* TypeMap: cleanup patches from previous commits
* TypeMapDatabase: fix passing GeneratorKind to FindTypeMap calls
* Stdlib.CSharp.cs: move std::map typemap from Stdlib.CLI.cs
* TypeMapDatabase: improve parameter name