Updated get-clean-data-proj run_analysis.R

- Applies the feature names to the columns
- Adds in the activity name and subject ID
Fixed typo in get-clean-data-proj Codebook

- Changed the second Walking Up Stairs to Walking Down Stairs
Compiled get-clean-data-proj Codebook

- Forgot to compile the fix to Codebook before the last commit
Completed get-clean-data-proj run_analysis.R

- Activity labels are now added as a factor vice string
- Added code to group the data and calculate the means
- Results are now written to a text file
Updated git-clean-data-proj .gitignore

- Added the summary-results.txt file to the list