Add arm specific configuration to help in the port.
Makefile changes to build on ARM
Add fake cpuid for ARM

TODO: proper implementation using procinfo
arm: use LLVM3.5
Rename Make.inc.arm to ARM.inc
Add checksums for llvm 3.5.0
Add basic ARM README
ARM.inc should have lower precedence than Make.user
Reorganize Make.inc to do detection earlier
add checked_{add,sub,mul} for BigInt
fix #5935 (rationalize returns curious/incorrect values)

Partially addresses #7501.
Merge branch 'arm-make3' of github.com:JuliaLang/julia into arm-make3

Conflicts:
	Make.inc
julia-mode.el: syntax entry for '/' and '.'

The division operator '/' was missing from the syntax table.  Also it would be better to classify '.' as a punctuation character.
Packages incompatible with your Julia version

If a package doesn't have any tagged versions compatible with your julia
version, it complains that

```julia
FixedPoint's requirements can't be satisfied because of the following fixed packages: julia
```
It seems confusing to consider julia a fixed package, so I changed the
message to.
```
ERROR: FixedPoint can't be installed because it has no versions that
support 0.4.0-dev+473 of julia
```
moji char predicates
update docs for character predicates
update helpdb.jl for character predicates
doc fix: rand(r) works also when r is a StepRange
doc fix: replace Range1 by UnitRange
fix eigfact doc (and a few :func:/backticks)