Add RStudio project files
Implement retrieve_raw_data in run_analysis.R
Record the download date in retrieve_raw_data
Outline the rest of run_analysis.R script
Implement Step 1 of the analysis in tidy_raw_data

Step 1: Merges the training and the test sets to create one data set.
Implement Step 2 of the analysis in tidy_raw_data

Step 2: Extract only the measurements on the mean and standard deviation
for each measurement.
Implement Step 3 of the analysis in tidy_raw_data

Step 3: Use descriptive activity names to name the activities in the
data set.
Implement Step 4 in tidy_raw_data

Step 4: Appropriately label the data set with descriptive variable names.
Do not reorder the variables
Implement Step 5 in summarize_tidy_data

Step 5: From the data set in step 4, create a second, independent tidy
data set with the average of each variable for each activity and each
subject.