change time format for migration module

improve the 'geturl'

If we have a url mapping like this:
`beego.Router(“/test”, &controllers.WeightController{},
"get:GetDetails”)`
when u use `UrlFor(“WeightController.GetDetails”, “foo”, 1, “bar”, 2 `,
it should return `/test?foo=1&bar=2` rather than `/test`.

// Getconfig throw the Runmode
// [dev]
// name = astaixe
// IsEnable = false
// [prod]
// name = slene
// IsEnable = true
//
// usage:
// GetConfig("string", "name")
// GetConfig("bool", "IsEnable")

Update captcha.go

Captcha must be deleted if the user entered a "challenge" with a different length than the captcha.

[orm] improve null pointer panic message

DefaultString(key string, defaultval string) string      // support
section::key type in key string when using ini and json type;
Int,Int64,Bool,Float,DIY are same.
	DefaultStrings(key string, defaultval []string) []string //get string
slice
	DefaultInt(key string, defaultval int) int
	DefaultInt64(key string, defaultval int64) int64
	DefaultBool(key string, defaultval bool) bool
	DefaultFloat(key string, defaultval float64) float64
	DIY(key string) (interface{}, error)
	GetSection(section string) (map[string]string, error)
	SaveConfigFile(filename string) error

revise the comment of SliceIntersect

The implementations of SliceDiff and SliceIntersect are the same.
However, the comments of them are opposite.
The former is (slice1 - slice2) while the latter is (slice2- slice1)