[guide] Build the Fluidity PyOP2 branch

The following assumes you have the fluidity-dev package from the fluidity-core PPA installed, which contains all dependencies for building fluidity:

sudo add-apt-repository ppa:fluidity-core/ppa
sudo apt-get update
sudo apt-get install fluidity-dev

Build the floppy_bn branch of fluidity:

bzr branch lp:~fluidity-core/fluidity/floppy_gn
cd floppy_gn
# This MUST be the same PETSc you've used to build PyOP2
export PETSC_DIR=/path/to/petsc
./configure --without-adjoint --enable-shared --enable-2d-adaptivity
make -j12
make -j12 fltools