Resolved some issues with header installation not working.
Created a photon_gn_t to contain the mechanics of photon correlation (correlator and histogram). This makes reuse of the code a bit easier.

Reorganized the build to first create a static library, which each executable then links to. This makes specification of a particular program's dependencies far simpler.

Fixed a bug in flid in which the intensity bins were not being normalized properly.
Intensity dependent gn code is now written, and is ready for proper testing.
Added some things to take care of.
Added the window width to flid and idgn. These are useful values for normalization.