[web_generator] Add Support for Parsing IDL Files (#377)

* integrated IDL single file parsing and integration testing

* modified interface idl input

* Completed support for Single IDL File Parsing
Fixes #374

* fixed suffix naming

* moved actual output from temp to `.dart_tool`

* made minor fixes

* Add newline to end of files

* Code resolution

* updated integration test suite

* Resolved all standing fixes to the integration test suite

* Update translator.dart