Release 2.0.0

• Added --legacy flag to allow use of legacy options (darth-tytus)
• Added --show [...] flag to show various extra bits of information for
  debugging/optimising (lyndonhenry)
• Query interface for provenance (yuli6313)
• Removed MPI support (b-scholz)
• Removed bddbddb and logicblox converters (b-scholz)
• Removed checkpointed evaluation (b-scholz)
• Extended inlining support (azreika)
• Added AST debug output for final 'optimised datalog' (mmcgr)
• Added RAM debug output (b-scholz)
• Updated man pages (darth-tytus/mmcgr)
• Fixes for AST/RAM printing (mmcgr)
• More useful debug output (mmcgr)
• Much more useful debug output (ohamel-softwaresecure)
• Interpreted souffle performance improvements (XiaowenHu96)
• Improved version output (mmcgr)
• Added support for floats and unsigned ints (darth-tytus)
• Improved testing (yuli6313/mmcgr)
• Added support for Record I/O (darth-tytus)
• Simplified error and warning messages (mmcgr)
• Added bitshift operators (ohamel-softwaresecure)
• Added support for polymorphic constants (darth-tytus)
• Improved aggregate performance (rdowavic)
• Added support for as(arg, type) (darth-tytus)
• Extensive refactoring of AST, RAM, utilities, and other bits (b-scholz and
  others)
• Improve Program Minimiser(azreika)
• Unrestricted number of columns per relation (before set to 64) (SamArch27)
• Generative functors (ohamel-softwaresecure)
• Refactor parser (ohamel-softwaresecure)
• Various bugfixes