Add CMake modules for finding xkb common
Use xkb common in CMake setup
Merge pull request #278 from neithernut/add-cmake-xkb_common

Add xkb-common to build setup
Add query for whether an object is an instance of a type
Add ws_transaction_push_statement() interface definition
Add implementation for ws_transaction_push_statement()
Merge pull request #286 from matthiasbeyer/add-transaction_functionality

Add a possibility to push a statement to a transaction
Merge pull request #283 from neithernut/add-object-is_instance_of

Add query for whether an object is an instance of a type