Quick start vignette for C++ use from R packages

[LTLA]

Closes #19. I used a vignette out of force of habit, but feel free to move it somewhere more appropriate.

[eddelbuettel]

Awesome. Will peruse and read.

Because I use Travis CI via this setup (of mine) we need to add
r-cran-knitr r-cran-rmarkdown to

rcppannoy/.travis.yml

Line 20 in 74bd7a9

- ./run.sh install_aptget r-cran-runit r-cran-rcpp

Can you please add that to the PR?

[eddelbuettel]

That did it. Had to restart one of the two subtests as the Ubuntu repo had timed out.

Will merge this. Would you mind if I converted this to using pinp which a few of my packages use for vignettes? I prefer pdf (but it's not a must -- I kept some other vignettes in html).

[eddelbuettel]

Also, I had some work piled up for RcppAnnoy incl a mini PR I pushed upstream to this will get rolled up soon I suspect.

[LTLA]

That's fine, I've no problems with pinp. Looking forward to the next release.

[LTLA]

Speaking of mini-PRs, I also pushed one upstream (spotify/annoy#313) so it'll be good if that could get into the next RcppAnnoy release as well.

[eddelbuettel]

Cool! I'll ping you before I roll this up, and if you follow this repo you'll see anyway when I commit.

I usually sync with whatever Erik has in his master at a point in time, so as you're merged you should be good.