Now with actual malloc/free implementations. Had to drop back to -O1
optimization because the ed25519 signature test broke with -O2. :(
Closes#153
The toolchain install and build process, for reference:
```
wget https://s3.amazonaws.com/mozilla-games/emscripten/releases/emsdk-portable.tar.gz
tar xvfz emsdk-portable.tar.gz
cd emsdk-portable
./emsdk update
./emsdk install latest
./emsdk activate latest
source ./emsdk_env.sh
cd ../TextSecure-Browser
grunt build
```
9e04910124