Work towards having vignette compile

As of this commit the vignette does not compile.

In devtools build_vignette() works just fine, but build() hangs.

R CMD build rentrez/ skips deletes vignettes as an empty folder
(which it is not!)
removed old inst files
fixed .Rbuildignore
removed non-ASCII chars from vignette
renamed vignettes
Merge branch 'vignette'

Vignette now works
removed old reference to 'untested' fxns in README