Copy generator.CamelCase for camel-casing names, with one change: Convert
'.' in names to '_'. This removes the need for the CamelCaseSlice function
which operates on a []string representing a name split along '.'s.
Add protogen.Message.
Reformat generated code.
Add regenerate.bash, largely copied from regenerate.sh.
Change-Id: Iecf0bfc43b552f53e458499a328b933b0c9c5f82
Reviewed-on: https://go-review.googlesource.com/130915
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
