Make sure texture unit 0 is active when reseting RenderTarget states (#523), fix RenderTarget not clearing when a texture used as a RenderTexture color attachment is left bound in a different context (http://en.sfml-dev.org/forums/index.php?topic=9350.0).
Fixed soundbuffer contents not being able to be updated when still attached to sounds (#354), sounds now detach from their buffer when it is reset. Signed-off-by: binary1248 <binary1248@hotmail.com>
Fixed issue where the viewport's width and/or height could be off by 1 pixel

Signed-off-by: Stefan Schindler <stefan@boxbox.org>
Fixed building for OpenGL ES 1.1 platforms

* Added proper extension handling for `glBlendEquation` and related
  constants (required for OpenGL ES 1.1).
Moved glClientActiveTexture and glActiveTexture calls before glEnable(GL_TEXTURE_2D) to make sure texture unit 0 gets affected. (#523)
Fixed potential memory leaks on OS X

And renamed create* methods to new* to follow more closely Objective-C
naming convention regarding memory management.
Removed a dead store in sf::Ftp implementation
Output error message and abort program when XOpenDisplay() fails

Fixes issue #508.

When the X11 display could not be opened, the application crashed without notice. Now, a meaningful error message is output to std::err() and std::abort() is called, causing immediate program termination.