add jl_get_cpu_name function to libjulia

thin ccall'able wrapper around llvm::sys::getHostCPUName
Modify jl_get_cpu_name to use jl_pchar_to_string,

add Sys.cpu_name
Move cpu_name into init_sysinfo()
Add back llvmcall
Import update llvmcall from cxx branch
Fix build for non-MCJIT versions of Julia & Add tests
Simple implementation of chmod(path, mode)

currently only integer modes, can do string modes like +x later
fixes #7574
Allow deletion of read-only files on Windows
Remove type constraints from intersect(::StepRange,::StepRange). This allows any range type where the step type implements lcm(), gcdx(), and mod() to use the method definition.
Revamp netload tests to more verbose and resiliient style
Fix nettest to run on multiple workers again
Whoops, accidentally reduced test case size
Improve performance of A_ldiv_B! for QR factorizations. Fixes #7887.

To get really good performance we need faster array views.
utf8proc -> libmojibake (closes #7656, fixes #7582)
Change the last two args of split/rsplit to 'limit' and 'keep' keywords. Fixes #6412
Add Pkg.whorequires to list packages depending on a particular package
Rename whorequires -> dependents
correct unparsing of Unicode binary operator expressions, getting precedences directly from julia-parser.scm rather than repeating them in show.jl
Check all packages, not just the installed ones
Adding proper header and footer (use M-x checkdoc to confirm).