add AC_CHECK_FUNCS([strchr]), suggested by autoscan
Create python tools library

Functions from convert_data.py have been pulled out and placed into library.
Other functions, including 'make_sample', to create the sample data set,
and 'read_maps', to read the maps output by mpi_makemap, have also been
added.
add some generated files and dirs to .gitignore
generalize some rules
add make_sample script to create sample data file
Create sample_data.h5 as target using make_sample script.
add pythonpath sample_data target
update to .gitignore