Fixed potential memory leak in sf::Font
Added documentation note on coordinates and undistorted rendering
Added String::replace() methods

Based on pull request #355 from abodelot
Updated copyright year to 2014
Fixed typo in Windows keyboard implementation

Fixes #516
Added String::substring() method

Based on pull request #355 from abodelot
Merge pull request #509 from ophui-/master

Fixed potential memory leak in sf::Font
Fixed forgotten members in sf::Font::operator=
Removed unnecessary null pointer checks in Window.cpp

Fixes #532
Avoided unnecessary toLower string conversions
Changed tabs to spaces in various files
Merge pull request #540 from tomgalvin594/convert_tabs

Changed tabs to spaces in various files
Adds name, vendor ID and product ID for joysticks.

- Implemented on Windows, Mac OS and Linux.
- Adds sf::Joystick::Identification structure to hold
  name, vendor ID and product ID.
Merge pull request #528 from NoobsArePeople2/joystick

Adds name, manufacturer ID and product ID for joysticks.
Added CMake find module for udev library
Image::flipVertically(), Image::flipHorizontally() optimizations.
Minor improvements in sf::Window and sf::RenderWindow documentation
Minor improvements in sf::Ftp documentation
Optimized sf::Listener with a cache

Two optimizations:
- Get functions return locally stored value
- Set functions call OpenAL only if value has changed
Exposed up vector in sf::Listener API

Closes #545