Emit remainder spaces

[sormuras]

Fixes #81 by emitting remainding spaces, that were not replaced by tabs.

[jbduncan]

LGTM, but I imagine this would change the behaviour of indentWithTabs for some Spotless users. What do you think @nedtwigg ?

[sormuras]

Perhaps, guard the new behaviour with a switch and call it like indentWithTabsAndEmitRemaindingSpaces(2) -- but removing the single space in front of each Javadoc comment line feels not right.

[jbduncan]

Sounds reasonable to me. However, I don't think "remainding" is a proper word in English. How about "remaining" (without the 'd') or "remainder" instead?

[sormuras]

Hm, I don't have an shell here atm to edit the commit message. Can you please squash and edit on-the-fly?

[nedtwigg]

I'm hesitant to change IndentStep. It is a possibly-breaking change in one of the oldest rules we've got. The current implementation can catch bugs of the following sort:

\t    \t    Good
\t    \t    Good
\t    \t    _Oops (where _ = a space)
\t    \t    Good

The suggested change would break this case. This mistake is easy to see, but the following is harder:

\t    \t    Good

\t    \t    Good

\t    \t    _Oops (where _ = a space)

\t    \t    Good

Advantage of existing implementation: Guarantees that all leading indentation will match exactly a multiple of the specified conditions.
Disadvantage of existing implementation: Doesn't handle indentation exceptions for comments very well.
Workaround: A fairly simple regex specific to these exceptions.

Advantage of new implementation: Swaps tabs and spaces without changing actual position of anything.
Disadvantage of new implementation: Doesn't enforce total amount of leading whitespace, just swaps the characters.
Workaround: ?