Merge pull request #774 from pmienk/master

Add custom 'src' target.
Move 'make code' from src/ to root.
Add custom 'src' target.
Document ZUUID_LEN (fixes #776)
Merge pull request #778 from rrthomas/master

Document ZUUID_LEN (fixes #776)
Probelm: zpubsub has been removed thus the examples shall be removed as
well
Solution: remove the examples for zpupsub -> they live now in zlabs
Merge pull request #779 from sappo/master

Problem: zpubsub has been removed thus the examples shall be removed as well