add checked_{add,sub,mul} for BigInt
fix #5935 (rationalize returns curious/incorrect values)

Partially addresses #7501.
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.
Fix hang/incorrect result for ndigits with b < 0.
Remove debug junk
Add tests for ndigits (issue #8266).
Move negative base check inside ndigits0z and add a test for (unsigned, signed) case.
ndigits: don't take abs(n) if b < 0.
Throw error when bigint ndigits has a negative base.
Merge remote-tracking branch 'julia/master' into ndigits_hang
Replace 'manual' cld with cld function now that #8111 has been merged.
Match previous ndigits0z interface.
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
incorporate comments from @sjkelly
Create julia.plist

BBEdit/TextWrangler codeless language module for Julia.
Fix tab completion segfault in reverse search
Merge pull request #8216 from JuliaLang/mn/rationalize

fix rationalize (#5935)