Fix long using time in 0.7

[MikaelSlevinsky]

No description provided.

[MikaelSlevinsky]

It appears that LowRankApprox.jl takes much longer to use. In 0.6.4,

sec-12-1610:~ Mikael$ exec '/Applications/Julia-0.6.app/Contents/Resources/julia/bin/julia'
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.6.4 (2018-07-09 19:09 UTC)
 _/ |\__'_|_|_|\__'_|  |  Official http://julialang.org/ release
|__/                   |  x86_64-apple-darwin14.5.0

julia> @time using LowRankApprox
  2.150360 seconds (6.88 M allocations: 379.468 MiB, 4.20% gc time)

sec-12-1610:~ Mikael$ exec '/Applications/Julia-0.6.app/Contents/Resources/julia/bin/julia'
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.6.4 (2018-07-09 19:09 UTC)
 _/ |\__'_|_|_|\__'_|  |  Official http://julialang.org/ release
|__/                   |  x86_64-apple-darwin14.5.0

julia> @time using FastTransforms
  2.707200 seconds (7.57 M allocations: 418.587 MiB, 3.77% gc time)

but in 0.7.1,

sec-12-1610:FastTransforms Mikael$ julia
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.7.1-pre.0 (2018-08-09 00:19 UTC)
 _/ |\__'_|_|_|\__'_|  |  release-0.7/36cddc1006 (fork: 51 commits, 38 days)
|__/                   |  x86_64-apple-darwin17.7.0

julia> @time using LowRankApprox
 18.936025 seconds (31.48 M allocations: 2.608 GiB, 2.46% gc time)

julia> exit()
sec-12-1610:FastTransforms Mikael$ julia
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.7.1-pre.0 (2018-08-09 00:19 UTC)
 _/ |\__'_|_|_|\__'_|  |  release-0.7/36cddc1006 (fork: 51 commits, 38 days)
|__/                   |  x86_64-apple-darwin17.7.0

julia> @time using FastTransforms
 21.781482 seconds (35.31 M allocations: 2.854 GiB, 2.81% gc time)

[dlfivefifty]

Once LowRankApprox.jl is tagged, this will be down to 6s.

[MikaelSlevinsky]

Awesome.

[dlfivefifty]

I think this is about the best we can do until Julia's compiler is fixed:

julia> @time using FastTransforms
  6.385736 seconds (14.82 M allocations: 1008.726 MiB, 4.55% gc time)