Add escaping to strings in list operation in BASIC

[dbuchwald]

Currently BASIC lists strings with special characters in not so nice way:

New program will be stored at location 0x331e
OS/1 Basic>100 print "Hello \"World\" \\!"
OS/1 Basic>run
Hello "World" \!
OS/1 Basic>list
100 PRINT "Hello "World" \!"
OS/1 Basic>