Package load time regressions in v1.8-beta3

Unfortunately the time regressions reported in April, pinged again about a month ago ago, were not fixed.

TTFP in 1.7

julia> tic(); plot(rand(5,2)); toc()
elapsed time: 7.5960746 seconds
7.5960746

TTFP in 1.8.0

julia> tic(); plot(rand(5,2)); toc()
elapsed time: 10.172608 seconds
10.172608