./couchbackup.sh should allow single URL parameter

[Mark Watson]

Modify ./couchbackup.sh to allow either

• a single URL that contains the full path to database
• a partial URL that contains a path to the Cloudant cluster and a separate parameter for the database name (as it is at the moment)

e.g. I should be able to do either

./couchbackup.sh https://user:[e-mail]/mydb

or

./couchbackup.sh https://user:[e-mail] mydb

[Mark Watson]

Fixed