Fix julia lu algorithm to handle singular matrices similarly to LAPACK.
tolerate stop_timer on a finalized timer. fixes most of #6075
Fix sprand for very small matrices
Fix construction of Qs for wide matrices. Fix printing of Qs.
Merge pull request #6064 from JuliaLang/anj/lu

Fix julia lu algorithm to handle singular matrices similarly to LAPACK.
only convert Array{T} to Ptr{T} or Ptr{Void} (fix #6073)
Revert "only convert Array{T} to Ptr{T} or Ptr{Void} (fix #6073)"

This reverts commit 97582fb0d54be66fa8d8b63a272f7ad7598b3f39.
Merge pull request #6076 from JuliaLang/anj/sparse

Fix sprand for very small matrices
base/printf.jl: the sig_dec function isn't used and can be deleted.
printf: complete support for BigInts (implemented ini_dec) [#5756]
deprecate conversion of Array{T1} to Ptr{T2} if T1 != T2 && T2 != None (fix #6073)
fix #6068, invalid IR for constant conditions in some cases
Merge pull request #6079 from stevengj/pointerpurity

deprecate conversion of Array{T1} to Ptr{T2} if T1 != T2 && T2 != None
make fallback hypot() behave the same for inf and nan as standard implementations
fix #6074, macroexpander bug in `let`
fix show() of 1-argument calls to binary operators

we were doing this:

```
julia> :((%)(x))
:(x)
```