Added cursor in TextBox, plus some other tweaks

ResetMode.java (modified) :
- Changed some code to new font.getDimension()

EntityDialogBox.java (modified) :
- Changed some code to new font.getDimension()

Font.java (modified) :
- Added function getDimension(String, int)
- Added function getCoordinates(String, int, int)
- Added function getCursor(String, int, int, int)
- Added function getCharacter(char)
- Removed function getWidth(String, int)
- Removed function getHeight(String, int)

GamePanel.java (modified) :
- Changed some code to new font.getDimension()

OptionPanel.java (modified) :
- Changed some code to new font.getDimension()

Button.java (modified) :
- Changed some code to new font.getDimension()

SelectionBox.java (modified) :
- Changed some code to new font.getDimension()

SelectionButton.java (modified) :
- Changed some code to new font.getDimension()

TabBar.java (modified) :
- Changed some code to new font.getDimension()

TextEdit.java (modified) :
- Changed some code to new font.getDimension()
- Added cursors, that are movable with right/left key and mouse