**Problem**

I merged #18 a little too soon; It has 3 issues:

1. It doesn't handle comment lines between nested properties
2. It doesn't handle a blank (whitespace) after `=` in the nested property opener like the other forms of properties.
3. The test case was inserted in the wrong location in `eini_tests` module; it should have been in its own test function, and it should have had some error cases.

**Solution**

1. Add support for comment lines in between nested properties.
2. Add support for blank after `=` in nested property opener.
3. Refactor and extend the tests for nested properties to cover more ground.

**Known Issues**

After I merged #18, I noticed this warning:

```
Compiled src/eini_lexer.xrl
Parse action conflict scanning symbol blank in state 51:
   Reduce to properties_nested from property_nested (rule 28 at line 97)
      vs.
   shift to state 53, adding right sisters to property_nested.
Conflict resolved in favor of shift.
```

It appears that the introduction of nesting has added some ambiguity to the grammar aroud the `blank`, and this change makes it a little worse:

```
Parse action conflict scanning symbol break in state 47:
   Reduce to single_value from blank (rule 44 at line 121)
      vs.
   shift to state 52, adding right sisters to blank.
Conflict resolved in favor of shift.

Parse action conflict scanning symbol blank in state 58:
   Reduce to properties_nested from property_nested (rule 30 at line 101)
      vs.
   shift to state 61, adding right sisters to property_nested.
Conflict resolved in favor of shift.

Parse action conflict scanning symbol comment in state 58:
   Reduce to properties_nested from property_nested (rule 30 at line 101)
      vs.
   shift to state 12, adding right sisters to property_nested.
Conflict resolved in favor of shift.
```

Now there is some ambiguity around `comment` as well, and this appears to cause an issue parsing INI files with a comment line at the end of a block of nested properties when another (not-nested) key follows. I don't know if we should mark this as a known issue or not, but the trigger case is in a commented unit test in `eini_tests`.

Resolves erlcloud/erlcloud#583

Encoding of source files in R17+ is utf8 by default, in R16 ascii, so utf8 strings removed from the tests altogether for compatiblity.

Erlang 19.x should fix this, so we'll either want to keep the tests
"fixed" like this for a long time or stop testing on Erlang 17 & 18.

The dash should really be supported as a title/key part. It it a commonly used "spacer" in titles and keys, and AWS INI files already support it.

Partially deals with accense/eini#2, but I have left spaces for another day—it is not clear what the policy should be here.

Binary and filename take over function to register ets table.

This fix bug of line number error.
Thanks to @Hexa.