v0.1 Release

• Support create, read, write and delete
• Use leveldb to manage namespace, support high performance list and rename
• Replica placement strategy and recover strategy
• Implement FUSE, support random write on small files
• 实现了文件创建、读写和删除接口
• 通过leveldb管理目录树，支持高效的list、rename
• 文件多副本冗余存储、宕机自动副本修复
• 通过fuse实现mount，并简单支持随机写