add gcc-4.8-multilib to .travis.yml
add gcc-4.8-multilib to .travis.yml

Maybe this will fix the gcc 32-bit build?

WebAssembly/wabt,citisolo/wabt,WebAssembly/wabt,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,WebAssembly/wabt,WebAssembly/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,citisolo/wabt,citisolo/wabt,WebAssembly/wabt