dorsal.sh checks PYTHON_EXECUTABLE variable for python executable to use. This fixes python version mismatches in the python build chain if multiple versions of python are installed on the system.
dorsal.sh also outputs lib64 directories to fenics.conf for 64 bit machines.
petsc.package looks for PETSC_EXTRA_PACKAGES environment variable for extra packages to download eg. sundials.
Redirected stderr of "which gdate" command to /dev/null in dorsal.sh
Added looking for local.platform package for platform configuration.
Added local*.platform to .gitignore.
Merged in poconbhui/dorsal/python-buildchain-version-fix (pull request #8)

dorsal.sh checks PYTHON_EXECUTABLE variable for python executable to use.
Merged in poconbhui/dorsal/fenics_conf-arch64-fix (pull request #9)

dorsal.sh also outputs lib64 directories to fenics.conf for 64 bit machines.
Merged in poconbhui/dorsal/petsc-add-extra-packages (pull request #10)

petsc.package looks for PETSC_EXTRA_PACKAGES environment variable for extra packages to download eg. sundials.
Merged in poconbhui/dorsal/which-gdate-fix (pull request #11)

Redirected stderr of "which gdate" command to /dev/null in dorsal.sh
Merged in poconbhui/dorsal/add-local_platform-checking (pull request #13)

Added looking for local.platform package for platform configuration.