Merge pull request #40 from jeff1evesque/doc_overview

#29: README.md, define 'Overview' subsection
#41: README.md, 'Execution' subsection require proper input text file
#41: README.md, minor language change
#41: README.md, 'Execution' subsection 'log/observation.log'
#41: README.md, minor language change
#41: README.md, minor language change
#41: README.md, minor language change
Merge pull request #42 from jeff1evesque/doc_execution

#41: Documentation: Further define 'Execution'
#41: README.md, describe the contents of 'input.txt', and 'observation.log'
Merge pull request #43 from jeff1evesque/doc_execution

#41: Describe contents of 'input.txt', and 'observation.log'
#41: README.md, minor language change
Merge pull request #44 from jeff1evesque/doc_execution

#41: README.md, minor language change
#41: README.md, minor language change
Merge pull request #45 from jeff1evesque/doc_execution

#41: README.md, minor language change
#46: README.md, fix minor typos in 'Overview' subsection