README.md files: Added copyright notes and removed the redundant media information
copyright added to all imp.k files
tutorial/4_imp++ revised to use the unified builtins
removed the env(...) wrapper for the environment recovery items
removed a forgotten K::= env(Map)
Merge branch 'imppp' of https://github.com/grosu/k into imppp

Conflicts:
	tutorial/1_k/4_imp++/lesson_7/imp.k
Merge pull request #371 from grosu/imppp

Imppp