added indmax,indmin,findmax,findmin for sparse matrices.

fixes #7577
Merge pull request #7578 from tanmaykm/tanmaykm

added indmax and indmin for sparse matrices.
Revert "added indmax and indmin for sparse matrices."
Merge pull request #7751 from JuliaLang/revert-7578-tanmaykm

Revert "added indmax and indmin for sparse matrices."
Use NTFS junctions to share/julia/base etc instead of Cygwin symlinks
Merge pull request #7752 from tkelman/cygwin-buildfix

Use NTFS junctions to share/julia/base etc instead of Cygwin symlinks
nano is 10^9 (profiling, fix #7720)
One more profile timer fix
Remove recommendation to use Mac-HPC compilers

They cause no end of trouble, e.g. #6244