seasonal harvesting from trees and shrubs

now we can harvest the fruit trees and blueberries, strawberries year after year.
also unified the harvest blueberries, strawberries and trees iexamine function.


tested and seems to work. comments welcome.
hah, i think i found it.... it is even wrong at my comment:
i call: 
has_flag("TFLAG_HARVESTED")
instead of: 
has_flag(TFLAG_HARVESTED)

the "..." made the difference...