PEGTL 2.5.0

• Added rules to match Unicode properties via ICU to contrib.
• Improved the Parse Tree / AST interface.
• Fixed parse tree node generation to correctly remove intermediate nodes.
• Added big- and little-endian support to the UTF-16 and UTF-32 rules.
• Added rules for UINT-8 and big- and little-endian UINT-16, UINT-32 and UINT-64.
• Added function to memory_input<> to obtain the line around a position.
• Added function to memory_input<> to start again from the beginning.
• Added example for Python-style indentation-aware grammars.
• Added examples for regular, context-free, and context-sensitive grammars.
• Added example for how to parse with a symbol table.
• Added automated testing with Clang 6.
• Added automated testing with Clang's -fms-extensions.
• Fixed build with Clang when -fms-extensions is used (clang-cl).