JuliaLang/julia — pull request #2953 by vtjnash (2013-04-28 00:36:18+00:00)
Title: add backtrace to warn and info

This adds backtraces to warn and info to make it easier to track down the offending line of code. e.g:
```
julia> using Winston
WARNING: has(d,k) is deprecated, use haskey(d,k) instead.
in warn at error.jl:67
in warn_once at util.jl:189
in has at deprecated.jl:17
in read at /Users/jameson/.julia/IniFile/src/IniFile.jl:42
in read at /Users/jameson/.julia/IniFile/src/IniFile.jl:68
in anonymous at /Users/jameson/.julia/Winston/src/Winston.jl:39
in include_from_node1 at loading.jl:90
in reload_path at loading.jl:113
in require at loading.jl:48
```

Any concerns or should I go ahead and merge?