Edited info about version

docs/samples/request_get.xml

@@ -1,5 +1,5 b''
 <?xml version="1.1" encoding="UTF-8" ?>
-<request version="1" type="get">
+<request version="1.0" type="get">
     <model>post</model>
     <filter>
         <id>id1/1</id>

docs/samples/request_pull.xml

@@ -1,5 +1,5 b''
 <?xml version="1.1" encoding="UTF-8" ?>
-<request version="3" type="pull">
+<request version="1.0" type="pull">
     <model>post</model>
     <filter>
         <version>3</version>

docs/sync.markdown

@@ -29,6 +29,11 b' Each post has an ID in the unique format'
 All requests pass a request type, protocol and model versions and a list of
 optional arguments used for filtering.
 
+Each protocol has its own version. Version consists of 2 numbers: first is
+incompatible version (1.3 and 2.0 are not compatible and must not be in sync)
+and the second one is minor and compatible (for example, new optional field
+is added which will be igroned by those who don't support it yet).
+
 # REQUESTS #
 Request types:
 * pull - pull the desired model ids