Support host count in machinefile

- Support the syntax `[user@]host[:port][*count] [bind_addr]` in the
  machinefile.
- Initial code just re-writes the list fed to addprocs() by repeating the host
  as specified, so there is no user-visible change.
Move the host count to the beginning: [count*]...
Remove trailing whitespace
Show closest candidates. Fixes #7686
Avoid `Real` overflow in `middle`
Update combinatorics.jl
make rational arithmetic use checked ops
Add rowvals(A) and nzrange(A, col) to make the sparse matrix interface a little friendlier.
writecsv for abstract arrays removed

fix #8675

writecsv method on AbstractArray is now removed (commented).
docs updated.
Patch openblas to add 64_ suffix when using 64 bit ints

objconv cannot do in-place modification of files

dont overwrite static library with objcopy on freebsd either

fix linking of arpack and suitesparse with 64_ blas suffix

the patched xlahqr2 was using UPPERCASE function names, and the probes
during arpack configure were using the C compiler, sgemm_ and cheev_
need to enable c preprocessor, and disable syntax error on long lines

SPQR also needed -DSUN64
add a separate blas_vendor for suffixed openblas
Fixes #8483 by correcting the auto completion on windows added some test cases + fixed an error that were discovered when doing `using B<tab>` before Pkg.init().
add hexfloat (%a) support for printf
add blasfunc for appending suffix to all blas and lapack symbols
add osx-only objconv dependency for renaming symbols
add .tar.xz and .zip files to source-dist
Document that break, continue, and goto are not allowed in @simd loops.
Merge Nullable types into the Types section of the manual.
Merge pull request #8704 from ArchRobison/adr/simddoc

Revise `@simd` documentation.
Merge pull request #8672 from simonbyrne/check-rational

make rational arithmetic use checked ops