Fix #2033
Rewrite of cov functions and matrix methods to tiedrank
Merge pull request #2035 from andreasnoackjensen/fixcov

Rewrite of cov functions and matrix methods to tiedrank
`cd` on windows. fixes #2011

I think this is all that was needed.

If I'm being naive please tell me as soon as possible, I'm getting really nervous not having a working windows build...
Merge pull request #2036 from WestleyArgentum/patch-5

`cd` on windows. fixes #2011
Fix windows build
Make LAPACK.gesdd allocate the correct size for rwork.

close #2024
Merge branch 'master' of github.com:JuliaLang/julia
Fix unix build that I broke with my last commit
Change IOStream to IO in show.jl
fix jl_eqtable_del and use delete-with-default in reload_path.

    julia> using Example
    in delete!: val not defined

@carlobaldassi's fix avoids this case, which fixes the immediate
problem, but the correct behavior here is to throw a key error:

    julia> using Example
    key not found: SOURCE_PATH

With a corrected jl_eqtable_del it's more elegant to write this:

    prev = delete!(tls, :SOURCE_PATH, nothing)
pkg/resolve: minor fixes

and lots of comments
(also added BitArray hashing)
Makefile: detect changes in base/pkg
pkg/resolve: optimized away gnrg
pkg/resolve: improved version pruning
pkg/resolve: check if solution is unsat