py-wasm: import version 1.2

Python module capable of decoding and disassembling WebAssembly modules
and bytecode, according to the MVP specification of the WASM binary
format.

As there is no official text format defined yet, the text format
implemented doesn't correspond to any existing definition and is a
simple `mnemonic op1, op2, ...` format. Functions are formatted in a
way similar to how Google Chrome does in the debug console.

(khorben)