Enabled KeyDown and KeyUp events in NativeWindow.
Implemented KeyDown and KeyUp events for Sdl2NativeWindow.
Implemented KeyPress event for Sdl2NativeWindow.
Add test for new text input events
Made DPI-awareness configurable (issue #6)

It is now possible to indicate that an application is not DPI-aware. In
that case, OpenTK will let the operating system handle DPI scaling. This
results in worse visuals (pixel doubling) but allows non DPI-aware
applications to continue working.
High-resolution mode is enabled by default
DPI-scaling should affect resolution

The correct resolution will now be reported depending on whether the
application is DPI-aware.
Fixed centering for non DPI-aware applications
Workaround for #5

WS_CLIPCHILDREN and WS_CLIPSIBLINGS appear to cause flickering on
specific video cards. OpenGL appears to work correctly without these, so
we'll disable them to return to OpenTK 1.0 behavior.
Corrected zip build script

Excluded items are now really excluded.
Ignore generated installers
Streamlined nsis installer

OpenAL is now included in the Dependencies/ folder and NShader is no
longer linked to by the installer.
Move installer to destination directory

This reduces the garbage left behind by the installer generation script.
Merge remote-tracking branch 'origin/master' into no-reflect