Merge pull request #161 from yunnysunny/master

修正了com.alibaba.druid.support.jconsole.model.GroupableTableHeader.isFocusTraversable()  中使用过期函数的问题
support filter autoload (SPI)
optimized DruidDataSource.getStatData lock
Merge pull request #162 from sandzhang/master

增加filter的autoload支持
profile support
Merge pull request #163 from wenshao/master

profile support
bug fixed & optimzed Histogram memory used
Merge pull request #164 from wenshao/master

bug fixed & optimzed Histogram memory used
use AtomicLongFieldUpdater instead of AtomicLong
use AtomicLongFieldUpdater instead of AtomicLong
Merge pull request #165 from wenshao/master

use AtomicLongFieldUpdater instead of AtomicLong
opimized memory used
Merge remote-tracking branch 'upstream/master'
opimized memory used
optimized memory used
Merge pull request #166 from wenshao/master

优化内存占用
getConnectCount with lock
change AutoLoad default value
profile support & add license info
Merge pull request #168 from wenshao/master

Profile支持