Clingo

* fixed bug in simplification of aggregates
* fixed bug with raw strings in macros
* fixed compilation issues with older glibc versions
* fixed output for enumeration of cautious consequences
* fixed bugs in clasp library
* fixed race in parallel model enumeration
* fixed incremental optimization
* fixed cleanup up of learnt constraints during incremental solving
* workaround for libstdc++'s bad choice for hash<uint64_t> on 32bit arches

* added clingo
* supports very flexible scripting support
* can cover iclingo and oclingo functionality now
* added stack traces to lua error messages
* added support for incremental optimization
* improved python error messages
* renamed gringo.Function to gringo.Fun
* removed luabind dependency
* removed boost-python dependency
* consistently use not instead of not as keyword for negation
* fixed translation of conditions in head aggregates
* fixed replacement of constants
* fixed grounding of recursive head aggregates
* fixed translation of head aggregates
* fixed show statements for CSP variables (condition was ignored)
* fixed plain text output of body aggregates
* added a ton of new bugs

* added scripting languages python and lua
* added -c option to define constants
* added constraints over integer variables
* linear constraints
* disjoint constraints
* show statements for constraint variables
* (experimental and subject to change)
* improved translation of disjunctions
* fixed include directives
* fixed preprocessing of definitions
* fixed lparse translation of optimization constructs