1.6.0

New

• Bolts now requires Xcode 7.0+.
  #212
  by @nlutsenko

Improved

• Specify generic type for BFTask.+taskForCompletionofAllTasks*().
  #217
  by @nlutsenko
• Remove nonnull requirement for return type from the block of BFTask.+taskFromExecutor(_ , block:).
  #218
  by @nlutsenko

Fixed

• Fixed compiler warnings on Xcode 7.3.
  #216
  by @nlutsenko