also:
- fixed a bunch of doxygen parsing issues
- added `#define` leak detection to the single-header script
- renamed `TOML_ALL_INLINE` to `TOML_HEADER_ONLY` (the old one still works too)
- simplified abi namespace definitions
also added support for wide strings on Windows (closes#42):
- added wide-string path arg overloads of `parse()` and `parse_file()`
- added wide-string support to all relevant `table` and `array` ops
- added `std::wstring` support to `node::value()` and `node::value_or()`
- added `std::wstring` support to `node_view::value()` and `node_view::value_or()`
- added wide-string overloads of `table::operator[]`
- added wide-string overloads of `node_view::operator[]`
- added `source_region::wide_path()`
- added `TOML_WINDOWS_COMPAT` switch for explicitly enabling/disabling this stuff
also:
- fixed internal macro `assert_or_assume` leaking out of `toml_parser.hpp`
- deprecated `node_view::get()` in favour of `node_view::node()`
- minor documentation fixes
- minor cleanup
- moved the main page to a separate dox file
- added integration section to homepage
- improved some of the examples
- formatting fixes
- added note about python wrapper (closes#36)
