Added basic folder structure and started Clock Tutorial
Added .gitignore files to preserve empty folders

Since git tracks files and not directories, parts of the base directory
structure were missing from the commit. Upon opening Unity, .meta files
for missing directories get cleared from the project. Having empty
.gitignore files within each directory effectively preserves the base
file structure.
Added time based rotation to clock hands.
Replaced spaces with tabs.
Renamed clock hand vars and added analog option.