OpenGL: invert alpha channel in shader code, too
Reset ClrMod when SetClrModulation is called without argument
Fixed CMake build on Unix
Removed unused parameter in C4MaterialMap::Load
Added includes and forward declarations to headers

So that they can be included individually
Added initial mape code, and added it to the CMake build system

The code is not yet working properly, but it compiles
TODO: autotools build, material colors, Material&Texture overload,
relicensing, maybe algo=script
Merged default into mape
Catch MapGenerator errors in mape, not in C4MapCreatorS2

Where it lead to a crash eventually, since it tried to Log the error message,
and Log is only allowed from the main thread - the Landscape is rendered by a
worker thread however.
Relicense mape under ISC

ack: Tyron, Armin
mape: Fix texture loading

We now not only load a texture's name, but also a thumbnail of the texture
itself, which we can show in the texview later, and from which we are going
to determine the material color to draw in the preview (note that the Color
field in .c4m files went away).
C4Group::GetFullName: Don't return an empty string for the root directory ("/")
GObject-ified MapeGroup
Follow GTK+'s single-include policy
Removed mape/ include path, include by "mape/foo.h" instead
Changed license headers of a few more files to ISC

They have been left out in e3b05cfc2145 for some reason.
Increased version number to 1.3.90, and added license text to about dialog
Actually committed new MapeGroup code
GObject-ified MapeMaterialMap
mape: Don't dynamically allocate memory for each pixel to draw
Merge default into mape