tiff: add utility commands and library options

Added support for compiling tiffcp and tiff2pdf.

Added options for compiling out various libtiff features. By default,
all libtiff features are built so that the result is the same as before
this change.

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>