Fixed Issue8 - GetInt() would fail trying to get an int from json

[tempcke]

Fixes #8

GetInt() would fail trying to get an int from json because all numbers in json become float64

From the docs: https://golang.org/pkg/encoding/json/#Unmarshal

To unmarshal JSON into an interface value, Unmarshal stores one of these in the interface value:

bool, for JSON booleans
float64, for JSON numbers
string, for JSON strings
[]interface{}, for JSON arrays
map[string]interface{}, for JSON objects
nil for JSON null

[tempcke]

@miladrahimi so will this get accepted in then?

[miladrahimi]

@tempcke Thanks for your contribution and making this open source package more useful.
Your changes are merged and released as v1.1.1