doxygen edits
Merge pull request #689 from dcoeurjo/doxygenEdits

doxygen edits
fix cmake warning
Merge pull request #693 from elcerdo/fixCmakeWarning

fix cmake warning
relax constraint on input image
documentation
Merge pull request #694 from elcerdo/fixConstImageAdapterConceptCheck

Fix const image adapter concept check
build examples option and prettier cmake messages
build examples option and prettier cmake messages
Merge pull request #695 from dcoeurjo/cmakeMinorEdits

Cmake minor edits