fix doc version
support unsafe_ref/assign for any isbits type, including pointer-free immutable composites
add pointer_from_objref (inverse of unsafe_pointer_to_objref)
update manual for pointer_from_objref and to note limitations on unsafe_assign
fix r"\u2220" bug mentioned in #107
remove B_str from exports and fix some formatting
fix #2514, "p=+\n1" should parse the same as "p=+"
do all unescaping and interpolation handling for normal strings in the parser
for custom strings, handle only \\ and \" in the parser
b_str no longer has interpolation (b_str should maybe be removed)
remove str, I_str, E_str, L_str, L_mstr, I_mstr, E_mstr
fixes #107
Merge pull request #2515 from stevengj/unsafe_immutable

RFC: extend unsafe_assign to work for any isbits type, add pointer_from_objref
fix #2086
why did this take 2 months?
immutability: make string types immutable.
immutability: make BigInt and BigFloat immutable.

This is slightly tricky since it requires moving the finalizer to the
data array inside of each of these, rather than the object itself,
but technically, that's more correct anyway, since if by some weird
circumstance multiple BigInts shared the same data array, the
finalizer should only be called on that data once.
immutability: make ranges immutable.
immutability: make regex-related types immutable.
immutability: make Stat immutable.
immutability: make sort Orderings immutable.
Merge branch 'master' of github.com:JuliaLang/julia
fix #2517, codegen of empty immutable structs
Merge branch 'master' of github.com:JuliaLang/julia
io::IO