The $@ option in bash doesn't make sense to come before `generate`
because the only option we can pass before generate cli usage is `help`.
System properties can be passed via JAVA_OPTS, so there's not really a
need for any intermediaries in the command line construction.
Having $@ at the end of the arguments list allows maintainers and users
inspecting options to quickly pass new options to a script. For example,
```
./bin/aspnetcore-petstore.sh --additional-properties sourceFolder=asdf
```
For command line arguments that may appear more than once in the
arguments list, this change doesn't provide any rules about overwriting
values that may exist (hard-coded) in the script. That is, in the
example above, if aspnetcore-petstore.sh already includes the
sourceFolder set to a different value, the "winning" value is up to the
options parser and openapi-generator-cli implementation.
* implemented core integration with play 2.4 ws
* added shell script to test on CI
* added shell script to composite file for all java generators
* added some comments
changed promise param to Response<T> to allow access to http status code and raw response if needed
* removed unnecessary whitespace changes
* added java7 compatibility, play ws deps to pom.xml
* added generated play24 client
* fixed imports
