Add more operators to StdOperators

- stricter use of UpdateQuery.set()
- Numbers just use their own type - PBaseNumber
- PEnum just uses its own type
- Expr.factory() to expose factory

ebean-querybean/src/main/java/io/ebean/typequery/PBaseNumber.java

@@ -7,7 +7,7 @@ package io.ebean.typequery;
  * @param <T> the number type
  */
 @SuppressWarnings("rawtypes")
-public abstract class PBaseNumber<R, T extends Comparable> extends PBaseCompareable<R, T, Number> {
+public abstract class PBaseNumber<R, T extends Comparable> extends PBaseCompareable<R, T, T> {
 
   /**
    * Construct with a property name and root instance.

ebean-querybean/src/main/java/io/ebean/typequery/PEnum.java

@@ -6,7 +6,7 @@ package io.ebean.typequery;
  * @param <E> the enum specific type
  * @param <R> the root query bean type
  */
-public final class PEnum<R, E> extends PBaseValueEqual<R, E, Object> {
+public final class PEnum<R, E> extends PBaseValueEqual<R, E, E> {
 
   /**
    * Construct with a property name and root instance.

ebean-querybean/src/main/java/io/ebean/typequery/TQRootBean.java

@@ -278,7 +278,7 @@ public abstract class TQRootBean<T, R> {
 
   /**
    * Specify the properties to be loaded on the 'main' root level entity bean
-   * also allowing for functions to be used like {@link StdFunctions#max(Query.Property)}.
+   * also allowing for functions to be used like {@link StdOperators#max(Query.Property)}.
    *
    * @param properties the list of properties to fetch
    */