Simple UI: removed obsolete DEBUG lines
SimpleUI: allow spaces around '=' and ':'
*UI: added reset command to set a leaf element to undef
*UI: allow also delete command on leaf element
*UI: added 'changes' command to list unsaved changes
*UI: fixed "save" command
SimpleUI: added missing doc
fixed term_ui tests for new changes command
*UI: list unsaved changes on propose to save on exit or quit
fixed term_ui test for reset command
Value: store a good value cancels the error stored in Instance
v2.047

    * Value: store a good value cancels the error stored in Instance
    * Term UI:
      * list unsaved changes and propose to save on exit or quit
      * fixed "save" command
      * added 'changes' command to list unsaved changes
      * allow also delete command on leaf element
      * added reset command to set a leaf element to undef
      * allow spaces around '=' and ':'
    * tweak cme-gen-class-pod so it can be run without cme (handy for tests)
    * Model generate_doc: write file if new doc is different from old
      (don't try to be smart with timestamps)