Added "swsbounce" magic: if this keyword is present in a <data> section it

sets the "swsbounce" magic mode. If there follows a request for the SAME
test number and the SAME part number, this mode will make the server bump
the part number internally and thus return a different <dataNUM> section
than it otherwise would.

Test case 153 uses this in case you need an example. It is pretty involved
and hard-to-use, but then the situation is pretty special over all. Enjoy.