bug fixed for log
add LogErrorf/LogWarnf/LogInfof/LogDebugf for formatter logging

using fmt.Sprint instead of fmt.Sprintln for logging print
fixed missing engine.LogWarnf replacement
Update session.go

fix stmt query of 'Get function' bug when an error occurred
Merge pull request #151 from starchou/master

Update session.go
bug fixed for mssql limit
Merge branch 'master' of github.com:go-xorm/xorm
fix syntax error in doc
add set type
Merge branch 'master' of github.com:go-xorm/xorm
SimpleLogger tidy up
Merge branch 'master' of github.com:go-xorm/xorm