Support "reset"

terminalframebuffer.cpp

@@ -306,3 +306,10 @@ void Framebuffer::delete_cell( int row, int col )
 {
   rows[ row ].delete_cell( col );
 }
+
+void Framebuffer::reset( void )
+{
+  int width = ds.get_width(), height = ds.get_height();
+  rows = std::deque<Row>( height, Row( width ) );
+  ds = DrawState( width, height );
+}

terminalframebuffer.hpp

@@ -127,6 +127,8 @@ namespace Terminal {
 
     void insert_cell( int row, int col );
     void delete_cell( int row, int col );
+
+    void reset( void );
   };
 }
 

terminalfunctions.cpp

@@ -439,3 +439,11 @@ void CSI_ECH( Framebuffer *fb, Dispatcher *dispatch )
 }
 
 static Function func_CSI_ECH( CSI, "X", CSI_ECH );
+
+/* reset to initial state */
+void Esc_RIS( Framebuffer *fb, Dispatcher *dispatch __attribute((unused)) )
+{
+  fb->reset();
+}
+
+static Function func_Esc_RIS( ESCAPE, "c", Esc_RIS );