fix a bug: array.tolist in numpy array.
fix a bug of result_indx in ./search/nearest.py
rename ./search/bilinear_box.py to ./search/bilinearbox.py, move ./search/build.py to ./interp/build.py
finished ./interp/interp.py and ./interp/algs/bilinear.py
add threp_dir.py and threp_import.py to ./interp and ./interp/algs, and tested bilinear.py.