Update Project Whitelist/Blacklist, README & Add .gitignore

[BenVlodgi]

• Setting the project to Blacklist None will allow it to build for all platforms and maintain marketplace compatibility. Having whitelisted platforms will often trigger the plugin to attempt a build on those platforms even when the user doesn't have the capability to build for those platforms.
• The gitignore excludes binary and intermediate folders as well as many other useful things in UE development.
• README updated to be better formatted & have link to example project.