Update Milestone entity and filters to comply with TestRail 5.3

pom.xml

@@ -157,8 +157,8 @@
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.5.1</version>
 				<configuration>
-					<source>1.6</source>
-					<target>1.6</target>
+					<source>1.9</source>
+					<target>1.9</target>
 				</configuration>
 			</plugin>
 			<plugin>

src/main/java/com/rmn/testrail/entity/Milestone.java

@@ -1,10 +1,12 @@
 package com.rmn.testrail.entity;
 
+import org.codehaus.jackson.annotate.JsonIgnoreProperties;
 import org.codehaus.jackson.annotate.JsonProperty;
 
 /**
  * @author jsteigel
  */
+@JsonIgnoreProperties(ignoreUnknown = true)
 public class Milestone extends BaseEntity {
     @JsonProperty("id")
     private Integer id;
@@ -45,4 +47,24 @@ public class Milestone extends BaseEntity {
     private Integer projectId;
     public Integer getProjectId() { return projectId; }
     public void setProjectId(Integer projectId) { this.projectId = projectId; }
-}
+
+    @JsonProperty("start_on")
+    private String startOn;
+    public String getStartOn() { return startOn; }
+    public void setStartOn(String startOn) { this.startOn = startOn; }
+
+    @JsonProperty("started_on")
+    private String startedOn;
+    public String getStartedOn() { return startedOn; }
+    public void setStartedOn(String startedOn) { this.startedOn = startedOn; }
+
+    @JsonProperty("is_started")
+    private String isStarted;
+    public String getIsStarted() { return isStarted; }
+    public void setIsStarted(String isStarted) { this.isStarted = isStarted; }
+
+    @JsonProperty("parent_id")
+    private String parentId;
+    public String getParentId() { return parentId; }
+    public void setParentId(String parentId) { this.parentId = parentId; }
+}

src/main/java/com/rmn/testrail/parameters/GetMilestonesFilter.java

@@ -7,7 +7,8 @@
  */
 public enum GetMilestonesFilter implements ApiFilter {
     //Request filter for get_milestones
-    IS_COMPLETED("is_completed");
+    IS_COMPLETED("is_completed"),
+    IS_STARTED("is_started");
 
     private String filter;
     GetMilestonesFilter(String filter) { this.filter = filter; }