DBOX 1.4 - like ECHO, except draws a double line box around
the text. May be freely distributed for non-military use
only. MASM/OPTAsm source included  Usage:

DBOX    Please insert the yellow diskette.

Leading and trailing blanks are removed from the string and one
blank is added to each end.  The result on the screen is:

+------------------------------------+
| Please insert the yellow diskette. |
+------------------------------------+

Except it will look better because DBOX uses the IBM double line
drawing set.  Version 1.4 allows you to change the left
margin if you reassemble.