Merge pull request #7524 from tkelman/pkg-test-travis

RFC: run pkg test on travis
Fix formatting error in eigs doc
Fix code block formatting error in control flow doc
Fix Makefile typo
Add orphan tags to non-default docbuild targets

The orphan tag suppresses Sphinx's complaints about their exclusion from certain docbuild targets
restore helpful message for sqrt(-1)
Merge branch 'master' of https://github.com/JuliaLang/julia
fix one more issue in commit 9b5b197695ebe05bb95cf60a0b028e3677529c8f
link libjulia with -lz, but not necessarily the julia executable
ref #4742
bring back --system-libs for LLVM >= 3.4
a change I needed to make USE_LLVM_SHLIB work
use llvm-config --ldflags both before and after --libs
base/operators.jl: remove harmful (incorrect) fallback for cmp.

This was causing cmp(Uint128,Uint128) to give wrong answers. The
other more general fallback that already exists is better.
Faster filt!

The array pointer loads cannot be hoisted out of the loop if this code
is in the same function that does the checking and potential
modification of b and a. This change gives a 1.2-1.5x perf gain. It
also mitigates potential effects of type instability of b and a due to
coefficient normalization.
Summary of module in documentation
Give suggestions for vector->row vector confusion

Some new users might get confused when they create a vector without
commas, and end up with a matrix that does not match the methods he
tries to use. After this patch the error will contain a suggestion.

```julia
julia> a = [1 2 3]
1x3 Array{Int64,2}:
 1  2  3

julia> sort(a)
ERROR: `sort` has no method matching sort(::Array{Int64,2})

You might have used a 2d row vector where a 1d column vector was required.
Note the difference between 1d column vector [1,2,3] and 2d row vector [1 2 3]
You can convert to a column vector with the vec() function
```
Merge pull request #7688 from ivarne/row_vec_suggestion

Give suggestions for vector->row vector confusion
Merge pull request #7698 from JuliaLang/sjk/faster_filt

Faster filt/filt!
fix bug in static_eval that could cause strange errors during bootstrap
restore branch-free cmp for Signed integers, plus test