Update README.md

This document describes the steps used to produce a tidy data text file containing variable means by subject and activity for a merged test and training file of "HAR" data.

- Set working directory
- Specify names of files containing key data (test, train, column labels, subjects, and activities
- Read data from files into specified data frames
- Set up column names for data frames containing subjects and activities
- Using the column labels, determine what columns contain mean and std information
- Determine the column indexs for columns containing mean and std information
- Subset from the data only those columns containing mean and std information
- Subset from the labels data frame only those labels for columns containing mean and std 
- Apply the labels to the subsetted test and train data frames
- Merge the test and train data frames
- Merge the subject and activity data frames respectively
- Column bind the subjects and activities DF to the right of the merged test and train DF
- Edit the column labels for clarity and readability
- Begin the process of creating a new tidy data file
- Use the aggregate function to create means by subject and by activity 
- Clean up the tidy data by removing subject and activity columns from the right side of the DF
- Rename the first &second columns from group.1 and group.2 to subject & activity respectively
- Write out the tidy data to a file, omitting the row names