Building our own PayPal button that can be translated and is accessible.

[kimcoleman]

All Submissions:

• Have you followed the Contributing guideline?
• Does your code follow the WordPress' coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Based on this older PR (#2074), I believe a better approach is to now just build this PayPal button ourselves. This way, it can be translated and is also more accessible.

We should consider this PR and close the other.

Examples of the button on 3.1 branch with both design options:

This PR also deprecates the pmpro_paypal_button_image filter.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you successfully run tests with your changes locally?

[dparker1005]

Just a note, our Add PayPal Express Add On should be updated to use the new button. I've opened an Issue in that repository to track this enhancement request.