simplify implementation of R.reverse
rename R.size and handle null/undefined argument
Merge pull request #542 from davidchambers/reverse

simplify implementation of R.reverse
Merge pull request #541 from davidchambers/length

rename R.size and handle null/undefined argument
clean up @return documentation
Merge pull request #557 from kedashoe/doc-fixes

clean up @return documentation
fix categorization of R.if
Merge pull request #558 from davidchambers/if

fix categorization of R.if