samples and html fix

runner/build.sh

@@ -3,4 +3,13 @@
 # "Compile rust source and put it as a tested contract"
 
 mkdir -p out
-rustc $1 -o out/contract.js -O --target wasm32-unknown-emscripten
+
+file=$1
+if [ ${file: -3} == ".rs" ]
+then
+    # Rust is compiled with rustc
+    rustc $file -o out/contract.js -O --target wasm32-unknown-emscripten
+else
+    # c/c++ can be compiled directly by emcc
+    emcc $file -Os -s WASM=1 -s SIDE_MODULE=1 -o out/contract.wasm
+fi