o   change default for ymd8 arg on dateParse() to TRUE
    o   make dateParse() use lookup tables for parsing
    	standard format dates (10 to 15x speedup)
    o   make underlying atomic type integer in dateParse()



git-svn-id: svn://svn.r-forge.r-project.org/svnroot/timewarp@48 edb9625f-4e0d-4859-8d74-9fd3b1da38cb