Delete examples/photoRec/README.html from repo
Edits to seminar03_graphics-lattice.rmd

* no code tidying
* fiddling with page title and header levels
* at least mention ggplot2
* replace hard-coded numbers, such as rows and columns in the dataset, with computed values
Link to seminar03_graphics-lattice; advertise the knitr, R markdown, git(hub) tutorial