Make hit maker always fill StEvent

Other cluster makers I can find in STAR software all do clustering based
on StEvent output, not StMuDst. Edit StFmsHitMaker so that the StEvent
fms collection is always filled if available. Given our current test
macro StEvent will be available, even though we are reading MuDST,
because we instantiate StEmcADCtoEMaker (I think!). This will allow
modification of the point maker to run using StEvent, so we can test it
in a more "realistic" setup.
Make point maker use StFmsCollection

Instead of getting trigger data from StMuDst and reconstructing hits,
use StFmsCollection accessed via StEvent. Given our current test chain
this works even though we are reading MuDST.
Remove FitTower dependence on TMatrix

FitTower constructor took a TMatrix argument, but it was only used to
set a row and column count. As neither row nor column were subsequently
used I removed them, the TMatrix arguments and other associated code.