hpi → fiff Relation

File in src/libraries/inv/hpi	Includes file in src/libraries/fiff
inv_hpi_data_updater.cpp	fiff_ch_info.h
inv_hpi_data_updater.cpp	fiff_info.h
inv_hpi_data_updater.h	fiff_dig_point.h
inv_hpi_data_updater.h	fiff_dig_point_set.h
inv_hpi_fit.cpp	fiff_cov.h
inv_hpi_fit.cpp	fiff_dig_point_set.h
inv_hpi_fit.h	fiff_ch_info.h
inv_hpi_fit.h	fiff_coord_trans.h
inv_hpi_fit.h	fiff_dig_point.h
inv_hpi_fit.h	fiff_dig_point_set.h
inv_sensor_set.cpp	fiff_ch_info.h