New option: --progress <arg> with dual meaning

Default behavior for progress updates (`--progress arg`) is like the current (2.0) multiplier.

To make this more useful without burdening the user with more options, you may either use an integer `N` to print updates every `N` examples or use a floating-point arg for multiplicative-period progress updates.

If the multiplier is <= 1, add 1.0 since the next update example counter must be bigger than current. e.g: 0.5 is would be interpreted as 1.5x

Also added two tests to RunTests.

Also cleaned-up some minor indent inconsistencies and misspelling I found along the way.