This generates a flow type for enums:
```noms
enum Handedness {
right
left
switch
}
```
Generates
```js
type E =
0 | // right
1 | // left
2; // switch
```
Issue #1081
The generated code for typed structs now uses a Go struct which
implements Value directly. The fields in this struct uses the "user"
type. (The union value still uses types.Value though.)
When a typed struct is created by the decoder, it asks for a struct
builder which returns a channel that the values of the fields of the
struct are sent to.
1) truncate filenames containing hash to only use first 7 chars of hash.
2) change output filename from <base>.go to <base>_noms.go
3) check for includes of file in same directory and don't generate twice.
Before encoding a compoundBlob we create a compoundBlobStruct and
encode that instead.
After decoding we check if the value is a compoundBlobStruct and if so
we convert it to a compoundBlob.
Fixes#455, #165
This makes the new typed serialization the default (the old
serialization is not used but the code has not been cleaned up yet).
Some things are no working in the new world:
Chunking - The compound list is not working correctly any more. The
Chunks method is having issues because it assumed things based on the
old implicit chunking.
Commit - uses a `Set(Commit)` which means that the parent commit is
embedded. We need to change that to be `Set(Ref(Commit))` so that the
parent commit is referenced instead.
Sets, Lists, Refs and Maps of imported types work now.
This PR also factors some of codegen.go into a separate package, to slim down
that file a bit.
Towards issue #294
