GO: Serialization

[yywing]

Following up #27 #1060

documented in https://doc.kaitai.io/serialization.html

branches:

• https://github.com/kaitai-io/kaitai_struct_go_runtime/pull/28
• https://github.com/kaitai-io/kaitai_struct_compiler/pull/261
  • base on https://github.com/kaitai-io/kaitai_struct_compiler/tree/serialization
• https://github.com/kaitai-io/kaitai_struct_tests/pull/101
  • base on https://github.com/kaitai-io/kaitai_struct_tests/tree/serialization

[yywing]

kaitai_struct_go_runtime:

• [x] add more function for compiler, make go translator like other language.
  • [x] if case
  • [x] err resolve
• [x] add function to support writer

kaitai_struct_compiler:

• [x] rewrite go translator supoprt writer

[mashiro01]

the changes we do:

• kaitai_struct_go_runtime

1. delete original reader and writer, and combined them into a new struct -> stream (like python and java's runtime)
2. for go, add a new rws(read, write, seek) buffer struct
3. for terminated string and bytes, add a new struct to describe them(util.go)

• kaitai_stricuct_compiler

1. splite common reader and common write into go reader and go writer (also works well for any other language)
2. rewrite go translator to support writer
3. complete functions in go compiler
4. some type conversions are fixed(support go's interface{})
5. clean up unuseful code generate

now we can use the compiler to generate go files which support serialize and unserialize

[yywing]

for terminated string and bytes, add a new struct to describe them

This change is used to calc length when write. We add this.SizeOf() to calc length of struct.