introduce new `panderOptions` for table alignment
resolve most often user error providing only one alignment instead of list of values
alignment option can be function too
alignment fn should also return separate `row.names` alignments
resolve issue with `pander()`
typo
fix: check if rownames are needed
split alignment option and introduce helpers
remove dummy default values as we have a global option
add tests for alignment options
Merge pull request #42 from Rapporter/align-option

new global options for table alignment -- fix #38