Optimize emcc linker flag (-O2), minifies JS output. Closes GH-45
Optimize emcc linker flag (-O2), minifies JS output. Closes GH-45

-O3 could also be used for increased optimization but it takes much
longer to link. Sticking with -O3 during compile and -O2 link for now.

satoshinm/NetCraft,satoshinm/NetCraft,satoshinm/NetCraft,satoshinm/NetCraft,satoshinm/NetCraft