Add multiple servers support to JS API client (#1974)

* add multiple servers support to JS ES6

* multiple server support in js es5

* using exports in es5

* fix index check

* add oas v3 js es6 client to travis

samples/openapi3/client/petstore/javascript-es6/docs/EnumTest.md

@@ -0,0 +1,60 @@
+# OpenApiPetstore.EnumTest
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**enumString** | **String** |  | [optional] 
+**enumStringRequired** | **String** |  | 
+**enumInteger** | **Number** |  | [optional] 
+**enumNumber** | **Number** |  | [optional] 
+**outerEnum** | [**OuterEnum**](OuterEnum.md) |  | [optional] 
+
+
+<a name="EnumStringEnum"></a>
+## Enum: EnumStringEnum
+
+
+* `UPPER` (value: `"UPPER"`)
+
+* `lower` (value: `"lower"`)
+
+* `empty` (value: `""`)
+
+
+
+
+<a name="EnumStringRequiredEnum"></a>
+## Enum: EnumStringRequiredEnum
+
+
+* `UPPER` (value: `"UPPER"`)
+
+* `lower` (value: `"lower"`)
+
+* `empty` (value: `""`)
+
+
+
+
+<a name="EnumIntegerEnum"></a>
+## Enum: EnumIntegerEnum
+
+
+* `1` (value: `1`)
+
+* `-1` (value: `-1`)
+
+
+
+
+<a name="EnumNumberEnum"></a>
+## Enum: EnumNumberEnum
+
+
+* `1.1` (value: `1.1`)
+
+* `-1.2` (value: `-1.2`)
+
+
+
+