Added accelerometer controls and vibration

* AndroidManifest.xml
- added permission for vibration
- added required feature accelerometer

* MonsterAssaultActivity.java
- changed configuration parameter - useAccelerometer to true

* Bob.java
- added vibration when Bob is hit

* BobController.java
- added constraints for Bob's hit, die and level change vibration
durations
- added vibration when Bob dies or level is changed
- reset level number to 1 when game is over so that new game starts from
level 1

* GameScreen.java
- added constant for accelerometer's threshold value
- removed touch-screen areas for moving left and right
- repositioned touch-screen areas for fire and jump to left and right
parts of the screen respectively
- added method to process input from accelerometer
- reset level number to 1 when game is exited by pressing back button
(or escape key on desktop)
Added HUD (health bar & score) and a new level

* GameScreen.java
- added a new Orthographic camera to render UI elements
- added constants for GUI camera's viewport width and height
- added constants for health bar's width and height
- added methods to render health bar and current score

* BobController.java
- Added bonus scores on level completion and game completion

* WorldRenderer.java
- removed method drawScore()
- removed unnecessary comments

* Other changes
- renamed levels 2 & 3 to level 3 & 4 respectively
- added new level as level 2
- modified level 1 to give new look
Added sound effects and icons

* BobController.java
- added static attributes for various sound effects
- added sound effect when bob jumps, hits the ground, gets hit, dies or
shoots
- added sound effect when level is changed

* Ball.java
- added static attributes for ball related sound effects
- added a sound effect when the ball collides with a block or an enemy

* Justin.java
- added static attributes for justin's hit and die sounds
- added a sound effect when jsutin dies or gets hit

* GameScreen.java
- added sound effect when the door for that level is unlocked

* LoadingScreen.java
- added loading of sound effects

* Bob.java
- added a sound when bob is hit

* GameOverScreen.java
- added a sound when game-over screen is shown

* MonsterAssaultDesktop.java
- Added config parameters for icons

* AndroidManifest.xml
- changed the name of launcher icons

* New Assets:
- various sound effect files
- multiple sized icons for desktop application
- multiple sized launcher icons for android devices