AplCircledAlpha resource

Description
When set to True, allows x3270 to work properly with special APL fonts like the APL385 font. APL385 maps the APL underscored alphabetic characters, which have no Unicode equivalent, to the Unicode circled-alphabetic characters in the range U+24B6 to U+25CF. Otherwise, the only way to display these characters is with one of the special 3270 fonts included with x3270.

Because this mapping is non-standard, this setting affects only the display. The Ascii action and Ascii1 action output underscored alphabetics as blanks, and copy-and-paste operations also represent them this way, though this may change to use the Unicode Combining Low Line character U+0332 at some point.