Topic: Rename to Introduction
Remove unnecessary comment
revise: CUDA+MPI > OpenCUDA+MPI
reivse: remove `microprocessor'
revise: significance: `section 2.1'

*   ``problem code'' > ``algorithm''

*   last two sentences > combine to one sentence
revise: `mpi4py`: it's > library's
reivse: testing: create new paragraph before list
revise: testing: cuda + mpi > cuda and mpi
revise: opencuda+mpi knowing > knowledge of
revise: write out 10 billion
revise: grammar fix, wrong article
revise: add missing future objective
revise: acknowledgements

*   add BSU before SRI

*   remove transition/ introductory phrase
revise: add introductory n-body paragraph
Merge branch 'revise_topic'
Merge branch 'revise_significance'
Merge branch 'revise_related_work'
Merge branch 'revise_methods'
Merge branch 'revise_results'
Merge branch 'revise_conclusions'