支持简短命令

[killme2008]

例如help敲h就够了，trace敲t就够了，类似gdb。

[zhongl]

这个可以有, 不过不在HouseMD实现支持, 得在Yascli中改进, 我已转移到那边的Issues了 CSUG/yascli#6

[zhongl]

cmd.alias

l CLASS = load $CLASS # a short cut of load 
is_xxx_run TIMEOUT = trace -t $TIMEOUT -l 1 xxx.run  # valid some method was being called
username = prop user.name # a short cut of show current use name
OS = env OS