Worked on more tests
Cosmetic changes
Closed #2: Added comment support
Update to #1: Support for unescaping quoted text
Closed #1: Added support for quoting on write
Renamed GetKeyArray to GetArrayKey

GetKeyArray could be understood as retrieval of key subset, instead of
retrieval of one key whose value is an array. GetArrayKey sounds more
intuitive.
Further work on type conversion

- Fixed defaultValue for GetKey<string>
- Removed nullable and struct requirement for GetKey<T>
- New parser option - controls whether conversion exceptions should be thrown
- Added tests.