Add date support
Minor fix
Remove exponent function from Dates
Only add attributes if there are any new ones
Fix minor error
Remove browser()
Add POSIXt support
Update put-/get-variable; changed type format: char -> integer
Fix some coding
Fix POSIXt in put-variable
Fix POSIXt in put-variable
Add variable name to messages/warnings/errors
Merge pull request #8 from SthlmR/issue6

Issue6