use paver instead of shovel

It is not using many features of paver, yet.
add Xilinx ISE project for manual implementation of single pendulum on FPGA
add test script for single-pendulum-vhdl
add test for float_to_sin
add test for cordic_sin
add test for float_from_sin and fix fraction width for float_from_sin (fixed point format on input and output of cordic is different)
fix test for float_sin and float_sin itself; add and test float_cos