0.7 compatibility

[ExpandingMan]

Just FYI, this doesn't work currently on 0.7. There lots of deprecation warnings that should be easy enough to fix but also:

As field: Error During Test at /home/expandingman/.julia/v0.7/FunctionWrappers/test/runtests.jl:21                                                 
  Test threw exception ErrorException("error compiling CallbackF64: error statically evaluating llvm IR argument")
  Expression: #= /home/savastio/.julia/v0.7/FunctionWrappers/test/runtests.jl:21 =# @inferred(f1(1)) === 1.0
  error compiling CallbackF64: error statically evaluating llvm IR argument                                                
  Stacktrace:                                                                                                                                   
   [1] macro expansion at /home/expandingman/.julia/v0.7/FunctionWrappers/test/runtests.jl:21 [inlined]                             
   [2] macro expansion at /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Test/src/Test.jl:1022 [inlined]
   [3] top-level scope at /home/expandingman/.julia/v0.7/FunctionWrappers/test/runtests.jl:17

which I have no idea what to do with.

[arnavs]

It would also be great (I think) to drop Julia v0.5 from Travis. At least IMO, the "build failing" warning triggers a level of apprehension or skepticism which is unwarranted in this case.

[yuyichao]

Fixed by 77ec3a4