Add a sample program: examples/histogram.php


git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@3080 92316355-f0b4-4df1-b90c-862c8a59935f

pipi_dither_ordered_ext, pipi_dither_halftone, pipi_median_ext, pipi_median,
   pipi_threshold, pipi_box_blur_ext, pipi_box_blur, pipi_get_command_list
Add sample program "examples/example1.php"


git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@3079 92316355-f0b4-4df1-b90c-862c8a59935f