
### Environment

* Dubbo version: dubbo-2.6.4
* Operating System version: windows 10
* Java version: JDK1.8

When run the testcase(com.alibaba.dubbo.config.AbstractInterfaceConfigTest#checkApplication1) in windows environment,It will be wrong. 

So It should add scene judgement in windows environment(org.apache.dubbo.common.utils.ConfigUtils#loadProperties(java.lang.String, boolean, boolean),Line 220).

```java
if (fileName.startsWith("/")) {
````
change to
```java
if (fileName.startsWith("/")||fileName.matches("^[A-z]:\\\\\\S+$")) {
````
the testcase (com.alibaba.dubbo.config.AbstractInterfaceConfigTest#checkApplication1) will go well.





* Extension list support<ul>
     * <li>Special value <code><strong>default</strong></code>, means the location for default extensions.
     * <li>Special symbol<code><strong>-</strong></code>, means remove. <code>-foo1</code> will remove default extension 'foo'; <code>-default</code> will remove all default extensions.
     * </ul>
     *
     * @param type Extension type
     * @param cfg  Extension name list
     * @param def  Default extension list
     * @return result extension list
     */
    public static List<String> mergeValues(Class<?> type, String cfg, List<String> def) {
        List<String> defaults = new ArrayList<String>();
        if (def != null) {
            for (String name : def) {
                if (ExtensionLoader.getExtensionLoader(type).hasExtension(name)) {
                    defaults.add(name);
                }
            }
        }
        List<String> names = new ArrayList<String>();
        
        String[] configs = (cfg == null || cfg.trim().length() == 0) ? new String[0] : Constants.COMMA_SPLIT_PATTERN.split(cfg);
        for (String config : configs) {
            if (config != null && config.trim().length() > 0) {
                names.add(config);
            }
        }
        
        if (!names.contains(Constants.REMOVE_VALUE_PREFIX + Constants.DEFAULT_KEY)) {