Implement acceptmallocleak_resourceusage

Type resourceusage_t was extended.
With function acceptmallocleak_resourceusage
it is possible to accept malloc memory leaks
up to 65535 bytes.

This is used by the graphics functions which
use EGL, X11 and OpenGL functionality.
These libraries do not free all memory.
Implement type display_t

This type wraps the native x11display_t and egldisplay_t
in a single type: display_t. This makes handling of graphic
displays independent of a native type and therefore the
source code more portable.

display_t supports OpenGL / GLES2 graphics.
Remove x11attribute_t

Was already by more generic windowconfig_t and surfaceconfig_t.
Implement window_t

The type window_t is an abstraction for
the native window type (only X11 at the moment)
and its OpenGL specific extension.

Other changes:

Integrated type display_t into surfaceconfig_t.

Renamed configuration values in KONFIG_USERINTERFACE
from KONFIG_xxx into XXX.
Changed konfig.h to define KONFIG_USERINTERFACE_XXX
for every XXX contained in KONFIG_USERINTERFACE.

Renamed configuration values in KONFIG_SUBSYS
from KONFIG_xxx into XXX.
Changed konfig.h to define KONFIG_SUBSYS_XXX
for every XXX contained in KONFIG_SUBSYS.

Changed interface of ONERROR_testerrortimer:
Pointer to err is now provided as a second parameter.
Add eventhandling to window_t.

Added eventhandler support to window_t.
The introduced type is window_evh_t which contains
for every event a pointer to a callback function.

Other changes:

A simplified static x11windowmap_t replaces splaytree_t
used in x11display_t to map ids to x11window_t objects.
This map will be replaced by a another index in the future.
Implement type pixelbuffer_t and gcontext_t

gcontext_t is an abstraction for the os specific
way to create an Opengl graphics context.

pixelbuffer_t is an abstraction for the os specific
way to create an OpenGL offscreen pixel buffer.

Other changes:

* Implemented eglcontext_t a wrapper for an OpenGL context using EGL as API.
* Implemented eglpbuffer_t a wrapper for an OpenGL pixel buffer using EGL.
* Renamed surfaceconfig_t into gconfig_t.