Updated tests to clarify current encoded & decoded values

The following tests have been added to show value conversion:

 - keys without a defined value
 - values consisting of just spaces to illustrate trimming
 - values consisting of quoted spaces to illustrate no trimming
 - a key without an equal sign, gets set to true as a bool
 - 'true', 'false', and 'null' get parsed as JSON
 - 'undefined' is not parsed as JSON

The following INI file ....

```ini
; Test blank value
s3 =

; Test value with only spaces
s4 =

; Test quoted value with only spaces
s5 = '   '

; Test quoted value with leading and trailing spaces
s6 = ' a '

; Test no equal sign
s7

; Test bool(true)
true = true

; Test bool(false)
false = false

; Test null
null = null

; Test undefined
undefined = undefined
```

Results in the following object:

```js
{
  s3: '',
  s4: '',
  s5: '   ',
  s6: ' a ',
  s7: true,
  true: true,
  false: false,
  null: null,
  undefined: 'undefined'
}
```