Document thread-safety issues in C callbacks
A new median of three quicksort that explicitly places the pivot in the right place after the inner loop. Additional performance gains were achieved after removing unnecessary bounds checking on the inner loop, as suggested by Kevin Squire.
Merge pull request #5081 from illerucis/new-quicksort

New Quicksort
Minor Dict-related performance enhancements

- Call `box` on ccall arguments in `bitmix`. Ironically this seems to
  be necessary to prevent the arguments from getting boxed.
- Use ifelse for NaN check when hashing Float32/Float64
OpenSUSE bumped their libexpat and zlib package numbers again
Whoops, missed a `prefix` check that didn't have `abspath()` in Makefile
improve type inference of type reflection (T.types, T.parameters)

ref #5752
Merge branch 'master' of github.com:JuliaLang/julia
preload base/userimg.jl if it exists.
Merge branch 'master' of github.com:JuliaLang/julia
Slight updates to $(prefix) and $(DESTDIR) handling inside of `make dist`
Whoops, need to NOT pass in absolute path to tar!
Merge pull request #5780 from JuliaLang/sjk/dict

Minor Dict-related performance enhancements
Multiarch recursive makefile variable fix
serialize/deserialize for Regex
Merge pull request #5788 from amitmurthy/amitm/regex

serialize/deserialize for Regex
Merge pull request #5657 from timholy/teh/doc_callbacks

Document thread-safety issues in C callbacks
windows: fix .julia path
fix #5798