Implement ability to set() struct and list fields by deep-copying from a corresponding Reader.  This copy requires no schema knowledge.

Mass rename 'reference' -> 'pointer'.  Been meaning to do this for a while -- all the documentation talks about 'pointers', not 'references'.

When an under-sized struct is found while traversing a builder, upgrade it to the expected size.  This is needed to allow easy copying from readers to builders.  Next, this will need to be implemented for lists as well.

Nope, Red Carpet does NOT work.  Back to Maruku, which also does not work, but in a way that is easier to work around.

Revamp dynamic struct getters/setters to not distinguish unions.  Add converience versions that take string names.

Dynamic API mostly done...  not tested.  This commit actually starts embedding the schema data in the generated code.

Restore ability to upgrade from List(Bool) to List(T) where T is a struct whose @0 field is of type Bool.  I previously disallowed this to reduce complexity, but it turned out to actually increase complexity.

Starting on dynamic message manipulation (manipluating messages without knowing the schema, or without compiling in the schema).

Delete Code Friday:  Inline structs/lists/data are too complicated for not enough benefit.  There goes a week of my life that I'll never get back.

Implement code generator plugins.  The Cap'n Proto compiler, when given -o foo, invokes the binary capnp-foo and passes the schema, in Cap'n Proto format, to its stdin.  The binary is executed with the current working directory set to the desired output directory, so all it has to do is write the files.

Implement 'Object' field type, which can be any pointer type.  The caller specifies the type when calling the accessors.