Packages incompatible with your Julia version

If a package doesn't have any tagged versions compatible with your julia
version, it complains that

```julia
FixedPoint's requirements can't be satisfied because of the following fixed packages: julia
```
It seems confusing to consider julia a fixed package, so I changed the
message to.
```
ERROR: FixedPoint can't be installed because it has no versions that
support 0.4.0-dev+473 of julia
```
Specify ::IO for writemime.
rm INFO message from Base.init_help; addresses #8290
Merge pull request #8352 from danluu/writemine_error_message

Specify ::IO for writemime
Add missing ARM dependencies.
Merge pull request #8358 from danluu/arm_blas_readme

Add missing ARM dependencies
Merge pull request #8355 from davidssmith/inithelp

rm INFO message from Base.init_help; addresses #8290
Fix OPENBLAS_OBJ_TARGET on Linux.
Add missing suitesparseconfig to JL_PRIVATE_LIBS.
Correct the inclusion of suitesparseconfig library.
Merge pull request #8271 from ivarne/pkg_error_message

Packages incompatible with your Julia version
Merge pull request #8362 from crayxt/patch-7

Add missing suitesparseconfig to JL_PRIVATE_LIBS.
Standardize openblas library symlink rule.
Remove promotion methods for Ax_ldiv_B(UMFPackLU,VecOrMat) in favor using the fallback verions.
Merge pull request #8361 from crayxt/patch-6

Fix OPENBLAS_OBJ_TARGET on Linux.