Build man-pages instead of distributing them in the source

Build man-pages instead of distributing them in the source

One less thing to do manual for releasing the code. And thus
avoiding to accidental releasing which old version of man-pages.

Writing copyright notice to stderr for all programs (was inconsistent)
and caused copyright notice to be displayed during build.

The CPack source package continues to contain the man pages pre-build.
CPack verifies that they are genenerated before building the source
package.

Added .isreposource to distinquish code obtained from git from code
downloaded as CPack source package.

Related to #645, #854, #735
Fixes #878

Change-Id: I7d7145fb99d3f1991d0f3992ca4f3ea20668dd9a