Add support for LCM1602 16x2 I2C LCD adapter

.travis.yml

   - sed -i 's/\/\/#define LCD_I2C_VIKI/#define LCD_I2C_VIKI/g' Marlin/Configuration.h
   - rm -rf .build/
   - DISPLAY=:1.0 ~/bin/arduino --verify --board marlin:avr:mega  Marlin/Marlin.ino
+  # LCM1602
+  - cp Marlin/Configuration.h.backup Marlin/Configuration.h
+  - sed -i 's/\/\/#define LCM1602/#define LCM1602/g' Marlin/Configuration.h
+  - rm -rf .build/
+  - DISPLAY=:1.0 ~/bin/arduino --verify --board marlin:avr:mega  Marlin/Marlin.ino
   # Enable filament sensor
   - cp Marlin/Configuration.h.backup Marlin/Configuration.h
   - sed -i 's/\/\/#define FILAMENT_SENSOR/#define FILAMENT_SENSOR/g' Marlin/Configuration.h

Marlin/Configuration.h

 
 //#define LCD_I2C_SAINSMART_YWROBOT
 
+//#define LCM1602 // LCM1602 Adapter for 16x2 LCD
+
 // PANELOLU2 LCD with status LEDs, separate encoder and click inputs
 //
 // This uses the LiquidTWI2 library v1.2.3 or later ( https://github.com/lincomatic/LiquidTWI2 )

Marlin/Marlin.ino

   #elif ENABLED(LCD_I2C_TYPE_MCP23017) || ENABLED(LCD_I2C_TYPE_MCP23008)
     #include <Wire.h>
     #include <LiquidTWI2.h>
+  #elif ENABLED(LCM1602)
+    #include <Wire.h>
+    #include <LCD.h>
+    #include <LiquidCrystal_I2C.h>
   #elif ENABLED(DOGLCD)
     #include <U8glib.h> // library for graphics LCD by Oli Kraus (https://code.google.com/p/u8glib/)
   #else

Marlin/ultralcd_implementation_hitachi_HD44780.h

   #include <LiquidCrystal_SR.h>
   #define LCD_CLASS LiquidCrystal_SR
   LCD_CLASS lcd(SR_DATA_PIN, SR_CLK_PIN);
+#elif ENABLED(LCM1602)
+  #include <Wire.h>
+  #include <LCD.h>
+  #include <LiquidCrystal_I2C.h>
+  #define LCD_CLASS LiquidCrystal_I2C
+  LCD_CLASS lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
 #else
   // Standard directly connected LCD implementations
   #include <LiquidCrystal.h>