message: Update INSTALL.MD
  Add install of gmp, and make needs to run with sudo
diff: - sudo apt-get install git
  - sudo apt-get install -y build-essential
  -#### Installing boost
  -- wget -O boost_1_64_0.tar.bz2 http://sourceforge.net/projects/boost/files/boost/1.64.0/boost_1_60_0.tar.bz2/download
  +#### Install boost
  +- wget -O boost_1_64_0.tar.bz2 http://sourceforge.net/projects/boost/files/boost/1.64.0/boost_1_64_0.tar.bz2/download
  - tar --bzip2 -xf boost_1_64_0.tar.bz2
  - ./bootstrap.sh
  - ./b2 -j8
  - sudo ldconfig ~/boost_1_64_0/stage/lib/ ~/libscapi/install/lib/
  -#### Installing OpenSSL
  +#### Install OpenSSL and GMP
  - sudo apt-get install libssl-ocaml-dev libssl-dev
  +- sudo apt-get install libgmp-dev
  #### Clone and build libscapi
  - git clone https://github.com/cryptobiu/libscapi.git
  - cd libscapi
  -- make
  +- sudo make
  #### Build and Run tests
  - cd ~/libscapi/test
  