Remove Clonable to fix StackOverflow

Potential fix for stackoverflow issue with Clonable.

app/src/main/java/com/todoroo/andlib/sql/DBObject.kt

@@ -2,7 +2,7 @@ package com.todoroo.andlib.sql
 
 import java.util.*
 
-abstract class DBObject internal constructor(val expression: String) : Cloneable {
+abstract class DBObject internal constructor(val expression: String) {
     var alias: String? = null
 
     abstract fun `as`(newAlias: String): DBObject

app/src/main/java/com/todoroo/andlib/sql/Field.kt

@@ -8,13 +8,9 @@ open class Field(expression: String) : DBObject(expression) {
     }
 
     override fun `as`(newAlias: String): Field {
-        return try {
-            val clone = clone() as Field
+        val clone = Field(expression)
         clone.alias = newAlias
-            clone
-        } catch (e: CloneNotSupportedException) {
-            throw RuntimeException(e)
-        }
+        return clone
     }
 
     fun gt(value: Any?): Criterion = UnaryCriterion.gt(this, value)