* Broker load supports function
The commit support the column function in broker load.
The grammar of LoadStmt has not been changed.
Example:
columns terminated by ',' (tmp_c1, tmp_c2) set (c1=tmp_c1+tmp_c2)
Also, the old function is compatible such as default_value, strftime etc.
After this commit, there are no difference in column function between stream load and broker load except old function.
