Add PkgResolve module, use it in Pkg

Substitutes the linear programming approach to
package resolution with a max-sum algorithm
PkgResolve: prune unnecessary versions
svd now returns U,S,V such that A = U*S*V.' - the same as matlab
svdt returns U,S,Vt such that A = U*S*Vt.
Return ctranspose(V) instead of transpose(V) in svd.
Allow building julia without an internet connection

Not sure what to do about deps/nginx, but clearly we can't require
internet just to build Julia.
rename: tls => task_local_storage in extras/test.jl [close #1999].
bump nginx version to release 1.3.11 (fixes e023596)
fix webrepl targets and quiet down STDIO not a pipe warning
PkgResolve: misc. improvements

*) fields no longer normalized
*) accuracy settable via environment variable
*) better handling of unsat cases
Fix: position() after skip() did not report correct position.
Update Travis to use llvm-3.2
Merge pull request #2003 from staticfloat/travisllvm32

Upgrade Travis to use llvm-3.2
re-fix SuiteSparse tests on mac & linux (replace a build-only flag
incorrectly removed during $(USR) -> $(BUILD) update)
fix USE_SYSTEM_GLPK and glpk target. fixes #2004
fix location of launch-julia-webserver.bat to be in webserver directory
Merge pull request #2001 from GunnarFarneback/ios

Fix: position() after skip() did not report correct position.
Make documentation examples current.
add importall. for #2002.
More documentation updates.
Merge branch 'master' of github.com:JuliaLang/julia