oAuth signatures are encoded by base64, that can generate plus signs.
See RFC 4648 <http://www.rfc-editor.org/rfc/rfc4648.txt>
By default plus signs in query params are replaced into spaces while
trying to access by super globals like $_GET and $_POST
Closes#13615
* Fixed case for all _e, esc_attr_e and esc_html_e strings
* Fixed case for all _n_noop strings
* Fixed case for all _x strings
* Fixed case for all __, esc_html__ and esc_attr__ strings
* Fixed a few more strings
* Fixed strings in unit tests
* Fix PayPal Standard case.
* Save Order text
Jaydeep Rami
Rasmus Bengtsson
Claudio Sanches
Claudio Sanches
Rami Yushuvaev
Aristeides Stathopoulos