Fix tests for saving and loading items.

Use NewVault() to create a properly initialized vault
for the test.
Support web form field and URL values in item templates

This allows the 'add' command to be used to create standard
login entries
Use case-insensitive sorting for 'list' command
Add 'rename' command to change item titles
Add optional pattern argument to 'list' command
Add note about what 1pass is for in the '--help' output