Pkg.generate refactor: GitHub user not needed to gen .travis.yml.
Fix #4623
Pkg.generate: `force=true` to regenerate files and leave unstaged.
Pkg.generate: on non-new rollback, do checkout in $pkg dir, not top.
Pkg.generate: cosmetic change.
Pkg.success: on Windows do `git update-index --really-refresh` first.

This hopefully will fix #4349 but may slow things down. Sigh.
replace ASCII banner with Julia logo image
README: make logo link to julialang.org in new window/tab.
Pkg/Windows: only `update-index --really-refresh` in non-bare repos.

Close #4349 again.
Pkg/Window #4349 a.k.a "package dirty, bailing", take 3.

So *this* git command always returns true but *prints*, yes, prints
the line "true" or "false". Seriously, git?
linalg/bitarray: bugfixes (istril/u, kron)

Also add tests
bitarray: implement preprend! and sizehint
bitarray: make bitshift operators saturating

This is for consistency with how those operators are
implemented for numbers.

Also, code cosmetics.
linalg/bitarray: additional check in dot

Also, code cosmetics
bitarray: remove some bound checks

Use inbounds macro where it makes a noticeable
difference (more than 10% performance increase).
bitarray: small improvement in kron
bug fix: missing d=0 default in spdiagm (from #4547)