Cleanup.
Documentation work.
Fix incorrect cursor position

When reactivating the cursor its position was updated visually but not
internally which caused glfwGetCursorPos to return wrong values.
Merge pull request #84 from Nibe/cursor-fix

Fixed saved cursor position not being restored.
Added forcing of swap interval on DWM composition.
Fixed window positioning on OS X.
Added blank cursor creation error checking on X11.
Enabled OpenGL 3.x and 4.x context on OS X 10.9.
Updated references to OS X (previously Mac OS X).
Fixed documentation tag name.
Updated OS X OpenGL compatibility docs.
Moved to auto-updated docs URLs.
Merge pull request #86 from siavashserver/master

Added utility functions for X11 error handler.
Cleaned up X error handler work.
Tagged close flag for use from secondary threads.
Added GLFW_OPENED to transition guide.
Moved X11 character translation failure test.
Cleanup of size_t use.
Changed scrollWheel to use precise scrolling deltas when available.

Use precise scrolling deltas only on supported versions of OS X;
hasPreciseScrollingDeltas, scrollingDeltaX, scrollingDeltaY are
available in OS X v10.7 and later.
Replaced a single occurence of a tab character with 4 spaces for
consistency in src/socoa_window.m.
Updated extension headers.