Support response model composition

[whunmr]

Describe the PR
Add support for inheritance/Model Composition in Response with allOf and ref.

syntax:

// @success 200 {object} jsonresult.JSONResult{data=proto.Order} "desc"
// @success 200 {object} jsonresult.JSONResult{data=[]proto.Order} "desc"
// @success 200 {object} jsonresult.JSONResult{data=string} "desc"
// @success 200 {object} jsonresult.JSONResult{data=[]string} "desc"

please see generated result in testcases of this PR.

Relation issue
#650

[codecov-io]

Codecov Report

Merging #651 into master will decrease coverage by 0.69%.
The diff coverage is 97.67%.

@@            Coverage Diff             @@
##           master     #651      +/-   ##
==========================================
- Coverage   85.74%   85.05%   -0.70%     
==========================================
  Files           7        7              
  Lines        1726     1800      +74     
==========================================
+ Hits         1480     1531      +51     
- Misses        154      171      +17     
- Partials       92       98       +6     

Impacted Files	Coverage Δ
operation.go	89.25% <97.67%> (-1.22%)	⬇️
schema.go	96.61% <0.00%> (-3.39%)	⬇️
parser.go	79.91% <0.00%> (-0.72%)	⬇️
gen/gen.go	96.85% <0.00%> (+0.02%)	⬆️

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[sdghchj]

LGTM

[sdghchj]

Thank you for your contribution.

[wujie1993]

awsome!!!

[sdghchj]

There is a bug for int, int32, int64 etc. which should be replaced with integer.
@whunmr Hope you fix it, please.

// @success 200 {object} jsonresult.JSONResult{data=int} "desc"
// @success 200 {object} jsonresult.JSONResult{data=[]int} "desc"

doc for data=int:

"responses": {
        "200": {
            "description": "desc",
            "schema": {
                "allOf": [
                    {
                        "$ref": "#/definitions/jsonresult.JSONResult"
                    },
                    {
                        "type": "object",
                        "properties": {
                            "data": {
                                "type": "int"   //here should be integer
                            }
                        }
                    }
                ]
            }
        }
    }