VI: all commands not seem functional.  Still at least on display artifact and probably some things not properly tested

NSH:  Add a break command; if-then-else and looping behavior can not be configured out of the build for small systems that need minimal scripting capability

NSH:  Loosen up if-then-else-fi syntx so that a command can be on the same line as the 'then' and 'else' tokens.  This allows, as an example, 'if true; then echo true; else echo false; fi' which is much more bash-like

If write buffering is enabled, then it is necessary to release the write buffer resources (callback structure) when the socket is closed