crossbuild-essential images: disable because of missing packages
crossbuild-essential images: disable because of missing packages

Temporarily disable because the packages are not available. See #209.

These should be replaced by crosstool-ng images.

thewtex/cross-compilers,thewtex/cross-compilers,dockcross/dockcross,dockcross/dockcross,dockcross/dockcross,thewtex/cross-compilers,dockcross/dockcross,thewtex/cross-compilers