REORG: ebtree: clean up remains of the ebtree/ directory

The only leftovers were the unused compiler.h file and the LICENSE file
which is already mentioned in each and every ebtree file header.

A few build paths were updated in the contrib/ directory not to mention
this directory anymore, and all its occurrences were dropped from the
main makefile. From now on no other include path but include/ will be
needed anymore to build any file.
11 files changed