added examples
various cleanup
add dfddva() function
add downstream() function
add upstream() function
break out matrix manipulation to the new diagonals package
add ffddva() function
add dfdfva() function
update README.md to reflect availability on CRAN
add gvc documentation file
re-add examples based on decompr 3.0.0
add vignette
initial release
nrca function
e2r function
i2e function