added iterators for tables and arrays

also:
- fixed parsing table headers allowing invalid characters
- fixed implicit fallthrough warnings
- fixed some issues parsing dates and times
- added `table::erase`
- added `array::operator[]`
- added `value::operator*`
- added stream operators for date, time and date_time
- added `impl::print_to_stream`
- added more parsing diagnostics
- added many tests

vs/toml++.vcxproj

@@ -65,6 +65,7 @@
     <ClInclude Include="..\include\toml++\toml_node.h" />
     <ClInclude Include="..\include\toml++\toml_parser.h" />
     <ClInclude Include="..\include\toml++\toml_node_view.h" />
+    <ClInclude Include="..\include\toml++\toml_print_to_stream.h" />
     <ClInclude Include="..\include\toml++\toml_utf8_generated.h" />
     <ClInclude Include="..\include\toml++\toml_table.h" />
     <ClInclude Include="..\include\toml++\toml_utf8.h" />

vs/toml++.vcxproj.filters

@@ -15,6 +15,7 @@
     <ClInclude Include="..\include\toml++\toml_json_formatter.h" />
     <ClInclude Include="..\include\toml++\toml_formatter.h" />
     <ClInclude Include="..\include\toml++\toml_version.h" />
+    <ClInclude Include="..\include\toml++\toml_print_to_stream.h" />
   </ItemGroup>
   <ItemGroup>
     <None Include="..\.editorconfig" />