Fix TokenHierarchy problem for NB7.3

If doc is not locked, the following exception is thrown on NB7.3:

INFO [org.netbeans.spi.lexer.MutableTextInput]: !!WARNING!! Missing READ-LOCK when accessing TokenHierarchy: input-source:org.netbeans.modules.csl.core.GsfDocument@12c5ad4, mimeType='text/x-php5', kitClass=null, length=150, version=1, file=org.netbeans.modules.csl.core.GsfDataObject@d2b470[/home/junichi11/NetBeansProjects/PhpProject3/app/View/Themed/Sample/Samples/index.ctp@872bb17b:7d5d85]
java.lang.Exception
	at org.netbeans.lib.lexer.TokenHierarchyOperation.ensureReadLocked(TokenHierarchyOperation.java:397)
	at org.netbeans.lib.lexer.TokenHierarchyOperation.tokenSequence(TokenHierarchyOperation.java:422)
	at org.netbeans.lib.lexer.TokenHierarchyOperation.tokenSequence(TokenHierarchyOperation.java:418)
	at org.netbeans.api.lexer.TokenHierarchy.tokenSequence(TokenHierarchy.java:186)
	at org.lorenzos.zencoding.zeneditor.ZenEditor.setup(ZenEditor.java:195)
	at org.lorenzos.zencoding.zeneditor.ZenEditor.<init>(ZenEditor.java:37)
	at org.lorenzos.zencoding.zeneditor.ZenEditor.create(ZenEditor.java:42)
	at org.lorenzos.zencoding.actions.ZenCodingAbstractAction.actionPerformed(ZenCodingAbstractAction.java:38)
	at org.openide.awt.InjectorAny.actionPerformed(InjectorAny.java:73)
	at org.openide.awt.ContextAction$Performer.actionPerformed(ContextAction.java:226)
	at org.openide.awt.ContextManager.actionPerformed(ContextManager.java:257)
	at org.openide.awt.ContextAction.actionPerformed(ContextAction.java:109)
	at org.openide.util.actions.ActionInvoker$1.run(ActionInvoker.java:93)
	at org.openide.util.actions.ActionInvoker.doPerformAction(ActionInvoker.java:116)
	at org.openide.util.actions.ActionInvoker.invokeAction(ActionInvoker.java:99)
	at org.openide.awt.GeneralAction$BaseDelAction.actionPerformed(GeneralAction.java:234)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
	at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
	at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:273)
	at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:272)
	at java.awt.Component.processMouseEvent(Component.java:6297)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3275)
	at java.awt.Component.processEvent(Component.java:6062)
	at java.awt.Container.processEvent(Container.java:2039)
	at java.awt.Component.dispatchEventImpl(Component.java:4660)
	at java.awt.Container.dispatchEventImpl(Container.java:2097)
	at java.awt.Component.dispatchEvent(Component.java:4488)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4575)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4236)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4166)
	at java.awt.Container.dispatchEventImpl(Container.java:2083)
	at java.awt.Window.dispatchEventImpl(Window.java:2489)
	at java.awt.Component.dispatchEvent(Component.java:4488)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:668)
	at java.awt.EventQueue.access$400(EventQueue.java:81)
	at java.awt.EventQueue$2.run(EventQueue.java:627)
	at java.awt.EventQueue$2.run(EventQueue.java:625)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
	at java.awt.EventQueue$3.run(EventQueue.java:641)
	at java.awt.EventQueue$3.run(EventQueue.java:639)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:638)
	at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Thanks.