Check float and double size
use function _M.func() type of declearation
Use c struct instead of lua table for segment
Remove rawget calls
Make "serialize" a method of message
Refactoring test_capnp.lua
Change e1's value from ENUM5 to ENUM7
Use nested schame
Remove unused code
Rename some files
Use import in proto/test.proto
Add a compiler. Generated file works.
Rename test.capnp to example.capnp
Add capnpc-lua.