variable-precision-0.1.1: THANKS

Robert P Munafo -- testing with ghc-7.0.4 resulted in fixes
  5318e8aac2fb75a9ecf9a3b661e911f610aa1784
    support old base with RealFloat required for Complex
  591fac0e024a41c2c31cde909385d36376e5a715
    support ghc-7.0.4 by increasing context stack size
  f7c89c0503b3038dc0057e0dc029db0dd98f2b0d
    document ghc-7.0.4 requiring increasing context stack size