Convert 'Hashdist' to the canonical 'HashDist' capitalization

With:

  $ sed -i 's/Hashdist/HashDist/g' $(git grep -l Hashdist)
  $ sed -i 's/HashDistdoc/HashDistDoc/g' $(git grep -l HashDistdoc)
Merge pull request #268 from wking/hashdist-capitalization

Convert 'Hashdist' to the canonical 'HashDist' capitalization