added new base64(...) function to base64-encode binary data, along with a Base64Pipe <: IO type
add multimedia I/O mechanism (display, mm_write, and friends)
fix #3982 (printf e/E failing)
Add bits() for Float16
document BitArray methods and add ref-links for math-operators in base
Merge pull request #3932 from stevengj/mimedisplay

RFC: add multimedia I/O mechanism (display, mm_write, and friends); fixes #3817
faster max and min for float arrays
Merge branch 'master' of github.com:JuliaLang/julia into jb/newvars
move newvar nodes after initial line number nodes