address CRAN check time issue

Flavor: r-devel-windows-x86_64 Check: Overall checktime, Result: NOTE Overall checktime 14 min > 10 min mainly from the sum of * checking examples ... [102s] OK Running 'testthat.R' [330s] * checking re-building of vignette outputs ... [176s] OK Please reduce the test timings by using - small toy data only - few iterations - or by running less important tests only conditionally if some environment variable is set that you only define on your machine? To do: - vignettes: precompile - [x] `knit_print` - [x] `rolling-crm` - [x] `trial_sanity_checks` - tests: skip the long running tests on CRAN - [x] `Design-methods` - [x] `Rules-methods` - [x] `Samples-methods` - [x] `Simulations-methods` - [x] `helpers-knitr` - [x] Confirm with `winbuilder` that we saved about half of the examples/tests/vignettes time now: yes* - [x] Submit again Now we get: * checking tests ... [61s] OK Running 'test-package-load.R' Running 'testthat.R' [59s] * checking for unstated dependencies in vignettes ... OK * checking package vignettes ... OK * checking re-building of vignette outputs ... [49s] OK