v3.1.0

Fixes:

• Fixed potential segfault when calling at_path() with an empty string
• Fixed UB in internal unicode machinery (#144) (@kchalmer)
• Fixed a number of spurious warnings with Clang 10 (#145, #146) (@chronoxor)

Additions:

• Added toml::array::for_each()
• Added toml::table::for_each()
• Added config options TOML_EXPORTED_CLASS, TOML_EXPORTED_MEMBER_FUNCTION, TOML_EXPORTED_STATIC_FUNCTION & TOML_EXPORTED_FREE_FUNCTION
• Added support for escape sequence \e when using TOML_ENABLE_UNRELEASED_FEATURES (toml/790)
• Added support for more unicode in bare keys when using TOML_ENABLE_UNRELEASED_FEATURES (toml/891)

Removals/Deprecations:

• Deprecated old TOML_API option in favour new TOML_EXPORTED_X options
  (it will continue to work as it did before if none of the new function export options are defined)

Build system:

• Meson: Added compile_library option (@Tachi107)
• Meson: Added ubsan_tests and ubsan_examples options
• Meson: Use system dependencies where available when building tests (@Tachi107)