Update SuiteSparse to 4.2.1
Fix #3482 - typo in socket.jl
readdlm improvements: use mmap by default. options to read header and ignore invalid characters
added tests
fixed travis tests
Merge pull request #3468 from tanmaykm/readcsv

readdlm improvements
corrected typo in PipeBuffer constructor
Merge pull request #3484 from tanmaykm/tanmaykm

corrected typo in PipeBuffer constructor
avoid boxing of more result values. should help #3485
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #3478 from staticfloat/suitesparse-upgrade

Update SuiteSparse to 4.2.1
Fix process chain handling in spawn

Fixes #3488
Reset SIGPIPE handler in child processes

Allows things like run(`yes` |> `head`) to not hang.