Basic working pulse graph page along with backend file that gets data
from database.
Forgot to change AJAX link to correct filename(getPulseData.php)
Minor updates

Tidied up code and added comments. Committing working version before
making renovations.
Search update

can input start and end dates to search. much slower.
updated pulseRatePage to output error messages (e.g. for invalid dates
or when query returns no results). the new file, pulseErrorMessage.html
merely contains the error messages (displayed through AJAX).

also added comments to all three files.
updated display to scatter plot. updated comments.