close instead of deleting cursor frame on show_cursor=false

add InputLine.open() and InputLine.close() methods to show/hide input line frames in the correct order, must less autotragically

InputLine.show_cursor = <boolean>
InputLine.cursor_attr = <color attributes>
InputLine.cursor_char = <character>

use InputLine.attr getter/setter instead of colors.bg/fg. persist control-a through multiple Frame.putmsg() calls. add auto_clear setting to Inputline

Surcease from sending additional header-termination newline (a blank line already appears after the headers.)

(frame.setData() ignores empty parameters, so a separate means of deletion is needed)

Brought back portions of the old sorting method to deal with these cases.
(This update probably needs more testing and review than I've given it.)

todo: score list pagination

Cleanup of async load/post URLs; assume that appendURL is at least / or that it begins and ends with /

added "transparency" mode option to Frame() objects. when enabled, any frame location where the character is undefined will return to the display buffer as being empty, and the next frame down will handle the call.

Removed tbHeader (we're not looking at header.thread_back any more.)

Service ports now included, hopefully minimizing times when sysop will need to mess with extra_ports in modopts

(To do: delete email, change read/unread status.)