isNumber accepts non-numbers

[drt24]

isNumber in escape.go is supposed to return true if it is passed a string that represents a number. However, it accepts "127.0.0.1" as a number but dot does not accept that. More generally it allows an arbitrary number of "."s in a number. This causes strings to not be escaped when they should be.

[drt24]

Possibly the best solution would be to just use the regexp from the dot specification: [-]?(.[0-9]+ | [0-9]+(.[0-9]*)? ) ? The regexp package is standard and with MustCompile the regexp would only need to be compiled once as the resulting Regexp is thread safe. https://golang.org/pkg/regexp/#Regexp

[awalterschulze]

Sounds like a good fix, would you want to make a pull request, or can I make the fix?
If you make a pull request, are you ok with giving over your copyright?