COMP: Update the .eps generation command to use the OUTPUT signature.

Use the supported signature for add_custom_command, get rid of the
SOURCE parameter, and use OUTPUT.

Since 000-ITKSoftwareGuide-Book1.dvi and 000-ITKSoftwareGuide-Book1.dvi
depend on ${allEPS-DEPS}, they will wait until the .eps file have been
created.

Change-Id: I07ec49e94f8bdfa7a5e10cd47a0bed2b9f07a3fb
Merge "COMP: Update the .eps generation command to use the OUTPUT signature."