xmd Code

Update version in xmd doc. Add clean options to Makefile. Update ChangeLog.

Update version number in doc.

Add warning message to use NSEARCH SORT when repeating bondaries are too small for NSEARCH CELL.

Update examples against latest xmd.

Renamed relax.rcv to writevar.rcv to match example name.

Fix WRITE VAR command in cdwrite.c.

Correct examples.

Fix POTENTIAL FORMULA PAIR command that was demonstrated in example 'formeam'.

Script to verify the XMD runs the examples correctly.

Fix example select_near_radius so that atom near point 1.9,1.9,1.9 is picked to prevent random changes in atom picked which throughs off the example verification program.