add string comparison assertion ShouldBeEqualIgnoringSpaces

looks like HEAD is broken, but still submitting this feature extension. Perhaps someone could fix HEAD and merge this? Thanks!

Jason

~~~
Jasons-MacBook-Pro:convey jasona$ go build
# github.com/glycerine/goconvey/convey
/home/jaten/go/src/github.com/glycerine/goconvey/convey/context.go:226: not enough arguments in call to reporting.NewScopeReport
Jasons-MacBook-Pro:convey jasona$ git blame context.go | grep 226
4bf4a34d (Robert Iannucci  2014-11-05 01:33:18 -0800 226)       ctx.reporter.Enter(reporting.NewScopeReport(situation))
~~~