* remove trailing space in cpprest, update samples
* add android batch files, better code format, sync petstore.json with
petstore.yaml
* restore petstore.json and sync it to petstore.yaml
* update circleci pom.xml
* add new android files
* add new android files
* apiInvoker : in getInstance, if instance is null initialize instance
build : replace the deprecated volley library by the android one
jsonUtil : Add in gsonBuider an adapter to deserialize Date class
And update petstore sample for volley library
* Update apiInvoker.mustache
Add a space after if, to stick to the code style.
* Update ApiInvoker.java
Add a space after if, in petstore samples, to stick to the code style.