expint.m: Overhaul function. Better accuracy and faster performance. Improved documentation and added %!tests. * scripts/specfun/expint.m: Improved accuracy of calculations by adjusting quad() tolerance options. Speeded up performance by breaking out of series summation as soon as possible. Used persistent variables to avoid re-calculating expensive intermediate values. Added %!tests verified against arbitrary precision Mathematica calculations.

*~
*.user
*.o
*.a
Makefile*
*.pdb
debug/
release/