Add data for bond valence parameters.
Fix header format, same data content.
Include cstdlib to declare getenv and setenv.
Include C headers as necessary.

Linux g++ is more sensitive on proper header includes.
Added the missing headers.
Remove obsolete variable.
Load BV parameters from runtime file.

Removed use of hardcoded static strings.
Include the bvaparm cif file with the installation.
Glob already finds version.hpp.
Rename DIFFPY_GITSHA to DIFFPY_GIT_SHA.
Add includes for all used functions.
Interface for scattering factors lookup.

Convert from Python-based lookup to runtimepath table.
Refactor class LineReader to runtimepath.hpp.
Add linestream instance data to LineReader.
Better name as this provides no class.
Lookup x-ray scattering factors in runtime table.
Fix include name and remove debug printout.
Use invalid oxygen ion to check exceptions.
Allow trailing zero charge when parsing atom ionization.
Use constant symbol string to lookup scattering factors.
Convert class SFTperiodictableXray to SFTXray.

Also lookup scattering factors from runtime files instead from Python.
Change the registry name from "periodictablexray" --> "xray".