v0.45.02_alpha

POSA corrected for some situations where incorrect values were returned.
Implemented inital functionality to support Flag 25, Data Error Ignore.
Prefacing a global label with '.' is a shortcut for XEQ. No intervening space character is required. For example, instead of XEQ TVM, typing .TVM will execute the label. This shortcut works in programs as well, but is expanded by LIST or SAVEP.
Implemented ERRNO which returns a number corresponding to the last error.
Changed initial error and last error state to MEMORY LOST , if lost (see Flag 59 explanation in the manual).
New command CLERR to reset the error number to 0 indicating no error.
New command XAIL executes one or more commands contained in the ALPHA register In Line. XAIL stands for "eXecute Alpha In Line".
When USER mode is enabled the prompt changes from ">" to "USER>" instead of a message being printed out to the terminal.
Fixed issue with XEQ starting a program even when a label wasn't found.