VS2010 does not support initialization lists
Merging alignup and int_ceil functions

These were doing same thing. Quick test showed int_ceil to be more
effective, so the new alignup uses int_ceil's impementation now.
Major overhaul of multivector expressions

* Multivectors and vectors now use same procedures for kernels
  generation and launching.
* Assignment of a multiexpression or a tuple of vector expressions to a
  multivector is now served by same method.
* Compound assignments to multivectors should be more effective.

refs #37
Removing unused code
fix bugs in fft_benchmark
clang complains about dependent template