修复ConcurrentModificationException的异常，当请求量比较大的时候
Update WebAppStat.java

去除多余的注释
improve sql parser
improve sql parser
improve output visitor
add logDiffrentThread 开关
improve MySqlParameterizedOutputVisitor
improve ParameterizedOutputVisitor
improve ParameterizedOutputVisitor
improve ParameterizedOutputVisitor
bugfix for sql Eval
bugfix
bugfix
fix #535
Merge pull request #543 from bucketli/master

fix #535
Merge pull request #512 from hadeslee/master

当session很多的时候，修复ConcurrentModificationException异常
Merge remote-tracking branch 'upstream/master'
bug fix
Update DruidAbstractDataSource.java