doc: Minor spelling fix

Signed-off-by: Sebastian Niemann <niemann@sra.uni-hannover.de>
devel: Fixed CMake config

- The project is now marked as CXX
- CMake <2.8 will throw a fatal error
- locate library with find_library(..)
- Set output directory to subfolder  ./lib
- Replaced PROJECT_BINARY_DIR with the correct root directory statement
PROJECT_SOURCE_DIR

Signed-off-by: Sebastian Niemann <niemann@sra.uni-hannover.de>
devel: Ignore output library folder

Signed-off-by: Sebastian Niemann <niemann@sra.uni-hannover.de>