fix #9214: canonicalize CompoundPeriod
implement rand(::Range{BigInt})

* Previously, calling e.g. rand(big(1:4)) caused a stack overflow,
  because rand(mt::MersenneTwister, r::AbstractArray) was calling
  itself recursively. This is fixed here, but a mecanism handling
  not-implemented types should be added.
* RandIntGen is renamed to RangeGeneratorInt.
* A type RangeGeneratorBigInt similar to RangeGeneratorInt (both
  subtypes of RangeGenerator) is introduced to handle rand on
  BigInt ranges. RangeGenerator is the generic constructor of such
  objects, taking a range as parameter.
  Note: two different versions are implemented depending on the
  GMP version (it is faster with version 6 on big ranges).
* BigInt tests from commit bf8c452112 are re-added.
Merge pull request #9122 from JuliaLang/rf/rand-bigrange

Implement rand(::Range{BigInt})
fix #9216: more consistent units for Period arithmetic
Merge pull request #9220 from stevengj/periodarith

fix #9216: more consistent units for Period arithmetic
Merge commit 'refs/pull/origin/9217'

Conflicts:
	base/dates/periods.jl
Add -O switch and add SLPVectorizer/BasicAliasAnalysis under it.
Change pass order to more closely match Clang's.
Add patch to LLVM 3.3 with enhancements for vectorizing tuples.
The patch contains functionality and tests backported from
SLPVectorizer changes added to LLVM 3.5.0.
juliatypes.jl: next round of failing tests
Merge branch 'master' of https://github.com/JuliaLang/julia
Update README.md

Adding Juno to the list of IDEs available.
remove deprecated functionality from base/ and tests/
Merge pull request #9230 from JuliaLang/jcb/rmdeprecated

Remove deprecated functionality (from v0.3) from base/ and tests/
fix #9231, type error deserializing function
Merge pull request #9229 from ribonoous/patch-1

Update README.md
Update README.md
small fixup for rand(::BigInt) and update docs

Now the runtime version of GMP is checked against the compile time
version, as suggested by @JeffBezanson. He also noted that the limbs
field of RangeGeneratorBigInt was not specific enough.
document __init__ (fix #8923)
Add URL to test failure error message. Fixes #9239.
Merge pull request #9240 from stevengj/init_doc

document __init__
Add convenience calls for rehashing

This is relevant particularly to precompilation, which requires
that any module global dicts get rehashed by the __init__
function.