Formatting, tabs vs spaces.

[Chris Fairles]

I've always been using 2 spaces instead of a tab character and setting
my tab width to 2. However, it seems that perhaps this isn't the norm?
For example, in the last commit that "fixed" time_point's indentation
shows up like this in some editors (like vim, my editor of choice, and
other gui editors that I use)

    template<typename... etc>
      struct time_point
      {
  typedef _Clock...
  typedef _Duration.. etc


i.e. the class contents here are only indented by what looks like 2
spaces but really its a single tab char and since my tab width is set
to 2, it doesn't display correctly. Should there not be 3 tab chars
here? or 6 spaces? Should I be using tab chars instead of spaces?

Chris