further cleanup
make input/output checks option
update speed vign
make figure for timings, use caching
fix cleanup of files
empty makevars, not needed any more
update using documentation
whitespace stuff
add latest vign binaries
add density function at all levels
add density tests, incl API
don't eval deliberate ERROR causing calls
document dtn1 API in using vign
demo dtn1() api usage
add latest vigns for easy dl
add density test for shift in distro
fix some documentation errors
add entropy calculation at all levels

- fixes #17
- includes test of correctness based on a test for a population mean
- includes API exposure
- includes API check
- has no input checks
add entropy API  and API check files
update changes documentation