Remove extra spaces on many lines

Most of these files had 5-space indents in some places,
occasionally with 3-space indents at a deeper level to confuse
things even more.

Corrected all indentation to 4 spaces.
Fixes N#216 - Landscape calculator layout with history

In landscape mode, keep the same button layout as portrait on
the right half of the screen, and replace the result with a
history view, including the operations. The history is scrollable,
and tapping numbers will enter them for the current operation.

Portrait mode behavior is mostly unchanged, other than a few
necessary tweaks to the calculator engine. The operation next
to the result was removed, because its behavior would have changed
and it is redundant anyway.

The current entry in landscape mode could use special styling to
make it more obvious, and it lacks the backspace key entirely.
Tapping numbers in the history is not very accurate.
Merge tag 'v0.0.9'

Conflicts:
	calculator.js
Remove debian packaging.
rpm: add packaging