Extended the plugin system to allow for dynamic runtime bindings between modules.

As a test implementation, this allows the TablesPage to open a CrudTab for a table/view without
the need for TablesPage, CrudTab and DatabaseWindow to know anything about each other.

pglab/plugin_support/PluginRegister.h

@@ -19,6 +19,8 @@ public:
 	PluginRegister();
 	void registerModule(PluginModuleSPtr module);
 	const ModuleMap& modules() const { return m_moduleMap; }
+
+	const PluginModule* findModule(const QString &module_ident) const;
 private:
 
 	ModuleMap m_moduleMap;