changes to spider: add padtemplates so the connect functions can connect two request-pad elements add a hack in gstel...

Original commit message from CVS:
* changes to spider:
* add padtemplates so the connect functions can connect two request-pad
elements
* add a hack in gstelement.c. please look at this, Company, and see how
we can get around this
* add backwards caps-propagation support in identity, int2float, float2int,
adder, speed, volume