This macro clears the SR (Shape Recognition) database and checks
the \verb+$MY_MEGAWAVE2/tmp+ directory (this one is created if you
don't have it already). 

The use of the SR macros implies to build a database of shapes, which
is located in the \verb+$BASEDIR+ directory (if you don't set this
variables, it will be set to \verb+$MY_MEGAWAVE2/tmp/SR_BASE+).
To build the database, call the macro \verb+PUT_TO_BASE+ with the
images you want to put in.

