Simplified request format. Now request type and version are in the root tag,

so the unsupported requests won't be parsed

docs/samples/request_get.xml

@@ -1,16 +1,8 b''
-<request>
-    <version>
-        <protocol>1</protocol>
-        <models>
-            <post>1</post>
-        </models>
-    </version>
-    <data>
+<request version="1" type="get">
         <type>get</type>
         <model>post</model>
-        <options>
+    <filter>
             <id>id1/1</id>
             <id>id2/56</id>
-        </options>
-    </data>
+    </filter>
 </request>

docs/samples/request_pull.xml

@@ -1,32 +1,22 b''
 <?xml version="1.1" encoding="UTF-8" ?>
-<request>
-    <version>
-        <protocol>1</protocol>
-        <models>
-            <post>1</post>
-        </models>
-    </version>
-    <data>
-        <!-- Request type -->
-        <type>pull</type>
-        <!-- Model which we wish to pull -->
+<request version="3" type="pull">
         <model>post</model>
-        <options>
+    <filter>
+        <version>3</version>
             <timestamp_from>0</timestamp_from>
             <timestamp_to>0</timestamp_to>
             <tags>
                 <tag>tag1</tag>
             </tags>
-        </options>
+    </filter>
         <hosts>
             <allow>
                 <host>*</host>
             </allow>
             <deny></deny>
             <pools>
                 <pool>test1</pool>
                 <pool>test2</pool>
             </pools>
         </hosts>
-    </data>
 </request>