IndexOutOfRangeException during execution of compiled templates

[abraham-fox]

Describe the bug

Handlebars.net throws IndexOutOfRangeException from HandlebarsDotNet.PathStructure.PathResolver.ResolvePath() on execution of compiled templates that have loose closing blocks.

Examples of templates:
{{#if 0}}test{{/if}}{{/unless}}
{{#if 1}}{{#unless 0}}test{{/if}}{{/unless}}{{/if}}

Expected behavior:

Handlebars.net compiler should catch this type of template errors during parsing and building expression trees and throw HandlebarsCompilerException with a meaningful error message.

Test to reproduce

[Fact]
public void TestLooseClosingBlockExpressionException()
{ 
    Assert.Throws<HandlebarsCompilerException>(() =>
    {
        Handlebars.Compile("{{#if 0}}test{{/if}}{{/unless}}")(new { });
    });
}