Update CITATION

Adding publisher's address to book citation.
Create bw.css

Adding black & white style file. Comments are italics and function names bold.
Alignment for HTML output with kable

https://github.com/yihui/knitr/issues/656
tweaking after #683; kable() supports alignment in HTML tables now
Adding more variations of the  B & W theme.
Changing to address to BOCO'
trivial typo
@export does what @S3method does now, although it is a little bit confusing
no address in the text version; let bibtex handle the address instead
roxygenize
there is no install-no-vignettes
I do not understand the error from Travis CI (example 051); there should not be an existing cache directory, but anyway
Table caption for format HTML, Latex and Prince

cf. https://github.com/yihui/knitr/issues/657
Changes asked by yihui