Groovy client for 0.90.X

Hi

elasticsearch-client-groovy seems not te be ok with 0.90.X branch. Whatever the [version](http://search.maven.org/#search|gav|1|g%3A%22org.elasticsearch%22%20AND%20a%3A%22elasticsearch-client-groovy%22) I tired, I got NoClassDefFoundErrors

Ooutput for 0.10.0 : 
```ruby
avr. 29, 2014 6:12:13 PM org.elasticsearch.plugins
Infos: [Deadhead] loaded [], sites []

java.lang.NoClassDefFoundError: org/elasticsearch/client/action/deletebyquery/DeleteByQueryRequestBuilder
	at java.lang.Class.getDeclaredMethods0(Native Method)
	at java.lang.Class.privateGetDeclaredMethods(Class.java:2531)
	at java.lang.Class.getDeclaredMethods(Class.java:1855)
	at org.codehaus.groovy.reflection.CachedClass$3$1.run(CachedClass.java:84)
	at java.security.AccessController.doPrivileged(Native Method)
	at org.codehaus.groovy.reflection.CachedClass$3.initValue(CachedClass.java:81)
	at org.codehaus.groovy.reflection.CachedClass$3.initValue(CachedClass.java:79)
	at org.codehaus.groovy.util.LazyReference.getLocked(LazyReference.java:46)
	at org.codehaus.groovy.util.LazyReference.get(LazyReference.java:33)
	at org.codehaus.groovy.reflection.CachedClass.getMethods(CachedClass.java:250)
	at groovy.lang.MetaClassImpl.populateMethods(MetaClassImpl.java:342)
	at groovy.lang.MetaClassImpl.fillMethodIndex(MetaClassImpl.java:292)
	at groovy.lang.MetaClassImpl.initialize(MetaClassImpl.java:3045)
	at org.codehaus.groovy.reflection.ClassInfo.getMetaClassUnderLock(ClassInfo.java:178)
	at org.codehaus.groovy.reflection.ClassInfo.getMetaClass(ClassInfo.java:194)
	at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.getMetaClass(MetaClassRegistryImpl.java:255)
	at org.codehaus.groovy.runtime.InvokerHelper.getMetaClass(InvokerHelper.java:859)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallConstructorSite(CallSiteArray.java:84)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallConstructor(CallSiteArray.java:57)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:182)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:190)
	at com.axa.elasticsearch.groovy.Monitor.init(Monitor.groovy:24)
	at com.axa.elasticsearch.groovy.Monitor$init.call(Unknown Source)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
	at com.axa.elasticsearch.groovy.MonitorTest.testStart(MonitorTest.groovy:10)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:84)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:74)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:211)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:67)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
Caused by: java.lang.ClassNotFoundException: org.elasticsearch.client.action.deletebyquery.DeleteByQueryRequestBuilder
	at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
	... 49 more
```

Also, it would be kind to update [online doc](http://www.elasticsearch.org/guide/en/elasticsearch/client/groovy-api/0.90/_preface.html) to explain which client version to use, for ```${es.version}``` is just wrong at the moment.

Thanks,
Yann