Lengthen the titleField and authorField
Upload book cover

Added the function to upload the book cover to parse.
Solve the bug

Solve the bug of not able to delete the row 0 of BookShelfTVC
Improved BookDetails Structure
Edit the background
Merge branch 'AddBook'
Created the status

1. Check if ISBN is nil
2. BookDetails can show the status
3. BWHelper changes the no to status
AddBookVC can now edit the status

1. Added the switch to AddBook
Merge branch 'Status' into AddBook
Merge branch 'AddBook'
Cannot request oneself books now
Bug solved: set the status when upload book
Merge branch 'Status' into AddBook
Merge branch 'AddBook'
Merge branch 'Request'
Set some request alert in bookDetails
Merge branch 'Request'