Changed cmake3 to cmake in Ubuntu build documents as there is no package named cmake3
cmake3 was throwing an error that the package did not exist. cmake exists and the build was successful using it.
@@ -251,7 +251,7 @@ wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key | sudo apt-key add -
sudo apt-get update
# All versions
-sudo apt-get -y install bison build-essential cmake3 flex git libedit-dev \
+sudo apt-get -y install bison build-essential cmake flex git libedit-dev \
libllvm3.7 llvm-3.7-dev libclang-3.7-dev python zlib1g-dev libelf-dev
# For Lua support
