now possible to call function in colormap
colormap &func accept arguments
change option --call to --begin and add --end
Fixed bug to accept empty colormap with field.
Change --of option to accept perl subroutine name.
Use modern style for preserving STDIN.
Fix bug of --if option.

Static filter command was duplicated when the file is matched with other filters.
Ex.  greple --if 'cat -n' gziped.gz
Make --of filter invoked for each files.
document update
Fix bug for handling empty color spec introduced by earlier change.