Additional tweaks to the build to build in ubuntu 15.04

Had to fight with the build a bit to get it to run fully on my box.
gcc 4.4 wouldn't work as wouldn't 4.9 (with different errors).

Here's what I did:

needed to install gcc-4.6 g++-4.6 gcc-4.6-multilib
needed to add a link to cc -> gcc
needed to add $ZEROVM_ROOT/bin to path

Just thought it might be worth it to update the docs or something.
