Added parametrized builds.

See new parameters for building PETSc using optional build dependencies
specified in profile.
Merge pull request #29 from hashdist/parametrized_prologued_builds

Added parametrized builds.
Update Tornado to 3.1.1

This is needed for the IPython Notebook from master.
Travis: Periodically update the terminal

* Enables "-v" for hit build (so that we can see full output)
* Saves the output from hit into log.txt
* Runs "pv" with 15 second intervals to keep Travis happy (this fixes a bug
  when some packages take more than 10 min to build)
* At the end we show the last 60 lines of log.txt for debugging

This should be enough to show most of the failures, yet Travis should be able
to finish the whole build even for very long logs.
Merge pull request #38 from certik/travis_pv2

Travis: Periodically update the terminal
Merge pull request #35 from certik/tornado

Update Tornado to 3.1.1
switched to permanent URL for HDF5 release
Merge pull request #40 from hashdist/hdf5-update

switched to permanent URL for HDF5 release
updated petsc examples and tests
Merge pull request #41 from hashdist/fix_petsc_test_and_doc

updated petsc examples and tests
Merge branch 'master' into xx