modules : added doc strings, fixed minor style issues, filtered from dependencies blacklisted modules

Add latest version of PnetCDF

add setuptools version 20.7.0

Replace py-setuptools version 20.5 by version 20.6.7

Spack was no longer using $TMPDIR for its stage area at LLNL. 

Spack was no longer using $TMPDIR for its stage area at LLNL. Spack's directory search was unnecessarily putting candidates that contained your username at the end of its search list.

Package global depends on ncurses

metis 5: fix download url

Spack picks up the wrong download for metis 5.1.0 from parsing
the url field for metis 4.0.3. Add an explicit url field to fix
this bug.

metis 4.0.3

fix : module files are deleted on uninstall (fixes #216)

Add bash package

Second attempt at PR#741

Add version 4.0.3 to metis package. Attempted to implement reasonable
versions of all variants declared for metis@5.1.0; some of these do
not have analogues in metis@4.0.3, and errors are raised accordingly.

Also updated dependencies of packages with depends_on('metis') to
depends_on('metis@5:') to ensure that these packages still build.

fix : mpich and mvapich2 will use spack compilers during installation

mpich : fixed wrong function signature

Conflicts:
	lib/spack/spack/test/database.py

  overwritten. These modifications were accepted as PR#741 but somehow I
  clobbered them when PR#742 was merged. There was some unintentional overlap in
  my local repository that I didn't straighten out before pushing.

modules : added skeleton to permit modifications based on specs

openblas: provide basename of compilers to avoid issues with detectio…