Provides LAPACK.stein!() and hooks in SymTridiagonal

Provides eigvecs() methods to return just the eigenvectors

in lapack.jl:
Changed LapackException to LAPACKException
Changed LapackDimMisMatch to DimensionMismatch

in tridiag.jl:
new eigvec method() to return just eigenvectors
optionally takes eigenvalues to return corresponding eigenvectors
miscellaneous cosmetic adjustments.
Git.transact: factor git repo state into an object.

Preparation for Git.transact support for submodules.
start_reading in read{T}(::AsyncStream, ::Array{T, N})
Explicitly declares iblock, isplit and w
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #2678 from jiahao/stein2

Provides LAPACK.stein!() and hooks in SymTridiagonal
Let qr and svd return thin matrices
Merge pull request #2685 from JuliaLang/anj/qr

Let qr return thin Q
Merge pull request #2684 from KDr2/kd/develop

start_reading in read{T}(::AsyncStream, ::Array{T, N})
close #2692
fix #2693, inconsistency in how TypeConstructor-valued arguments get cached
update precompiles
Partially address #2689.
The install-git target still needs to be done right as discussed
in #2689.
add the ability to store only array dims and not total length, to save space
Merge branch 'master' of github.com:JuliaLang/julia
fix svd and eig on numbers
improve type-related properties of that code
remove eps() for Complex
Doc updates for #2673 (thin factorizations by default)
Modify openblas interface bitwidth check to support openblas compiled as a generic libblas replacement