[PATCH] Some code improvements (no functional change)

[Duncan P. N. Exon Smith]

> On 2014 Jun 12, at 08:42, Chandler Carruth <chandlerc at google.com> wrote:
> 
> I'm lacking context sadly. =/

Idea is:

  - SwapByteOrder takes args by value and returns swapped bytes.
  - Some users want to swap in place.
  - So, rename SwapByteOrder => getSwappedBytes.
  - Then, add swapByteOrder (which takes and modifies a reference).