fix #2360 (BitArray ref/assign performance)
bitarray: remove some useless definitions
bitarray: change .^ following 1d82980562
fix #2254 again
Merge branch 'master' of github.com:JuliaLang/julia
Merge branch 'master' of github.com:JuliaLang/julia into jb/immutable
cleanup conversions to BigInt,BigFloat

This adds a few missing conversions (e.g. Bool->BigInt), promote
rules and constructors. Also adds tests.
Fix stack overflow creating ComplexPair{BigFloat}
Merge branch 'master' of github.com:JuliaLang/julia into jb/immutable
complete RTS changes for jb/immutable to the point where it compiles again