FillPDF Service 7.0.5: Minor account page improvements and 75%/90% usage notifications

The latest version of FillPDF Service includes a couple improvements:

- By request, I've added automatic email notifications when you reach 75% and 90% of your allocated plan usage. This gives you some time to allow overages or upgrade and not get surprised. You can disable the notification in your user profile (click Update email/password, then look for "Disable" near the bottom).
- The API key field is now visually hidden when you first come to the user page. You can click on API Details to view it.
- There is now a convenient link to configure whether you want to allow overages or not, and the setting has been moved up on the page to make it easier to notice.