Fix class loading in ArchiveClassLoader

As per my thread [here](http://www.vinsert.org/showthread.php?440-Regarding-class-loading), I suggest you make this change so that the class path does not interfere with client class loading.
For example, if a class file in the same directory as the jar is named "c.class", the bot will throw the following exception when attempting to load a new client:
```java
    Exception in thread "bot0" java.lang.NoClassDefFoundError: c (wrong name: c/c)
    	at java.lang.ClassLoader.defineClass1(Native Method)
    	at java.lang.ClassLoader.defineClass(ClassLoader.java:787)
    	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    	at java.net.URLClassLoader.defineClass(URLClassLoader.java:447)
    	at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    	at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    	at java.security.AccessController.doPrivileged(Native Method)
    	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
    	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    	at java.lang.ClassLoader.findSystemClass(ClassLoader.java:1046)
    	at org.vinsert.bot.loader.arch.ArchiveClassLoader.loadClass(ArchiveClassLoader.java:313)
    	at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
    	at client.init(Unknown Source)
    	at org.vinsert.bot.loader.HijackLoader.create(HijackLoader.java:102)
    	at org.vinsert.bot.Bot.run(Bot.java:90)
    	at java.lang.Thread.run(Thread.java:722)
```