java.lang.IllegalAccessException with property named isFoo

If i pass an object with property name like **is**_Foo_ the render fail with the error:
Exception in thread "main" java.lang.IllegalAccessException: class com.soywiz.korte.dynamic.JvmObjectMapper2 cannot access a member of class Person with modifiers "private final"
at java.base/jdk.internal.reflect.Reflection.newIllegalAccessException(Reflection.java:392)

Here's a simple code to replicate the error

```
import com.soywiz.korte.Template
import kotlinx.coroutines.runBlocking

fun main(args: Array) = runBlocking {

val templateString = """My name is {{ name }} and {% if isBusy %}I'm{% else %}I'm not{% endif %} busy"""
val data = Person("John Doe", true);
val renderer = Template(templateString)
println(renderer(data))
}

data class Person(val name: String, val isBusy: Boolean)
```

When I rename "isBusy" with a name that doesn't start with "is" (e.g. hasTime ) the error disappears.

Start with com.soywiz.korte.dynamic.JvmObjectMapper2, named in the exception, and run the Kotlin reproduction using a data class property named isBusy. Done means the template renders the isBusy condition without IllegalAccessException, while the equivalent non-is property continues to work.

Written by the indexing model from the issue text.