Rearranged the UI info section

Changed colors and positioning of the high score and current score
fields. Also added time elapsed in minutes and seconds and obstacles
remaining until next level as two separate UI fields.
Added documentation for getTimeElapsed() method.
Consider the level in getting score

Score increased due to the game speed of each level.
Add some test point for pushing UP, DOWN and SPACE keys.
Increase and decrease velocity

By pushing UP arrow key the velocity is increased.
By pushing DOWN arrow key the velocity is decreased.
Reset the current speed at each level

By starting a new level, current speed reset to the game speed of that
level.
Show Current Speed

Add the current speed number on the frame.
Add pause feature

Click space to pause and un-pause the game.
Change score calculation

Change score calculation to have the effect of current speed and level.
Add Moving Obstacle

Number of moving obstacles equal to the level + 1 are added to each
level
Decrease lives after Moving Obstacle Collision

Lives decreased after the car collision to the moving obstacle
Change speed of moving obstacles

Change the speed of moving obstacles due to the level of the game.
Add Level Info to the frame

Show the level of the game in the frame.
changing graphics
New images for moving obstacles

New images for moving obstacles are added to media folder.
Some correction in the moving range of the obstacles in x axis.
Make MovingObstacles as extends of HoleObstacle
Merge pull request #1 from saeedkf/master

Request to merge our changes to the Racecar