Composite transform fixed parameter fixes

@ntustison @stnava 

Nick and Brian,  We have been working on several enhancements to antsRegistration to improve performance and to make forward and inverse transforms more robust.

This set of patches has been tested and completely passes the regression test suite with 100% success.  It also takes advantage of work done by Ali Ghayoor earlier this year in ITKv4 to allow each stage of registration to begin where the old linear transform stopped, but without the speed penalty of using composite transforms.

In a very short 5min test, this provided a 6.4% speed improvement over the previous implementation.  We are working on larger scale tests right now.