Make some sections to be optional in the config file.

- Version description, keywords, software, privacy and support urls.
- Game Center.
Refactor image handling:

- Add normalize image names, support folders and prevent conflicts.
- Refactor the screenshots section in the config file.
Update examples.
Update readme
Merge pull request #14 from mmacvicar/fixes_and_refactors

Fixes and refactors
Multiline support for version_whats_new. Bumped version number to 0.4.5
Added license
allow screenshots with the same file name for different locales

For this, the locale is added in the generated filename
Bumped version
Update README.md
Add support to parse transporter files