Add missing generators

[HugoMario]

We can notice that generator list for 3.0.0 is shorter than 2.X. The main reason for this is because converting mustaches templates to handlebars templates has made the migration process slow. but since the generator support both template engines now, we can accelerate this generator migration, using the same templates located on swagger-codegen v2.

Here are the list of missing generators:

• ada
• ada-server
• akka-scala
• android
• apache2
• apex
• aspnetcore
• bash
• clojure
• cwiki
• cpprest
• csharp
• csharp-dotnet2
• dart
• eiffel
• elixir
• elm
• erlang-client
• erlang-server
• finch
• flash
• python-flask
• go
• go-server
• groovy
• haskell-http-client
• haskell
• javascript
• javascript-closure-angular
• java-vertx
• jmeter
• lua
• lumen
• nancyfx
• nodejs-server
• objc
• perl
• pistache-server
• powershell
• python
• qt5cpp
• rails5
• r
• restbed
• ruby
• rust
• rust-server
• scala
• scala-lagom-server
• scalatra
• scalaz
• php-silex
• sinatra
• slim
• swift
• php-symfony
• tizen
• typescript-angularjs
• typescript-aurelia
• typescript-fetch
• typescript-jquery
• typescript-node
• undertow
• ze-ph

Looks like there are a lot to do, any help is welcome. By my side, i'll start adding those most used/requested generators, based on filed tickets created those generators.

[HugoMario]

scala and akka-scala have been added with #176. thanks a lot to @rbiersbach for helping with this.