always check major version when comparing version numbers; load methods package for testing just to be sure
include command used for comparing graphics into output of failing tests; also check if number of failed pixels is NA
add missing method drawDetails.tikz_node

this was responsible for the failure of the grid_annotate test
work around ggplot2 bug; adjust for slight change in dimensions
evaluate() and raster graphics don't play well, work around by using eval() and try(); minor modifications in raster test results
fix failing test by showing less characters
ignore test files
update NEWS
install package for running unit tests

- after installing LaTeX
run unit_tests on Travis as part of a build matrix