[1] Configure gradle wrapper

Configure the gradle wrapper to allow people to build the project
without the need to install gradle and configure it
[1] Add sdk folder

The folder will be kept in the repo to allow the build and running
of the sdk by gradle
[1] SDK modifications

Modification to the gradle config to allow testing from the SDK
Addind the SDK folder to gitignore to prevent repo clash
between intelligid and intelligid-sdk