#12 - Add warning that there are unsaved changes in the edit study form

[Karim-C]

This pull request (fixes issue #14) makes the study edit/create forms more user-friendly and more error-tolerant. When the user has unsaved changes while they are editing/creating a study, they are warned of these unsaved changes when they try to navigate away from the form. They will receive the warning when they:

• cancel out of the form
• when they try to close the window
• when they try to reload the page.

This addition prevents the user from inadvertently exiting out of the form and losing their work.

[Karim-C]

@AprajitGandhi and @wilmol can you please review this pull request.

[Karim-C]

@softeng-701 all team members have approved this pull request.