Add Clear CLI function

Sometimes it would be nice to clear the screen if it has a lot of
information (ex: when in debug information). Some terminals support ^L
to clear screen, but not all (iTerm2 on my mac does not), so I think
this is worthwhile to add.

Edit: Forgot cli.h

Debug/cli/cli.h

@@ -108,6 +108,7 @@ void CLI_tabCompletion();
 // CLI Command Functions
 void cliFunc_arch    ( char* args );
 void cliFunc_chip    ( char* args );
+void cliFunc_clear   ( char* args );
 void cliFunc_cliDebug( char* args );
 void cliFunc_device  ( char* args );
 void cliFunc_help    ( char* args );