Adds hello world tour examples.
Organizes the example.s
Adds a section called tour basics.
Packages.
removes lang.
Imports.
Functions continued.
More basic examples.
More basics
Minor edits.
Numeric constants.
For.
If.
If and else.
loops and functions.
Interesting code.
Compile right.
Switch.
Defer.
Defer multi  -- stacked execution.