code formatting cleanup / improvements

[adeelhasan]

1. follow the conventions in formatting a long line from source code
2. add comments, esp. parameter documentation
3. change order of parameters so that tokenId is always the first one
4. tidy up the spacing between blocks
5. rename variables / improve readability

[adeelhasan]

• moved all the structs out of the library; a library would be a better fit if there were also some functionality to go with the struct; it also makes the code easier to read without the LicenseStructs being prefixed for references to a struct (eg LicenseStructs.License vs License)
• changed the layout of the file to have the private/internal code to be towards the bottom
• removed references to "cycle"

[adeelhasan]

more cleanup tracked separately