Across the project there are many coding styles with lots of different
indentation patterns. There are three different tabs to space
conversions (1:2, 1:4, 1:8), even mixed within individual files. This
makes the code unnecessarily hard to read and to edit.

In the hope that I do not offend anybody: unify code style.

Roughly apply the style from kdelibs:

* get rid of all tabs
* indentation is four spaces
* unify includes and include guards
* less blank lines
* one space after "if", "for", etc.
* no space after cast
* prefix operators ("++", "--") instead of postfix where applicable
* pointers: preferably single space before "\*" (same for "&")
* opening curly braces on same line except for implementations
* no whitespace after opening parenthesis "(" or before closing ones ")"
* no single line "if", "for", "else", etc. (always curly braces)
* indent "case" to same level as corresponding "switch"
* at least in some files adjust line wraps to a limit of 100 chars
* exac...