WIP: Support 0.6

[dlfivefifty]

This starts updating to support Julia 0.6, dropping 0.4 support (though it could probably be restored using @compat if desired.) The biggest change needed to work around is the addition of RowVector.

The Laguerre tests currently fail due to quadgk no longer being in Base:

Laguerre tests
ERROR: LoadError: LoadError: quadgk(fcti,0,Inf) has been moved to the package QuadGK.jl.
Run Pkg.add("QuadGK") to install QuadGK on Julia v0.6 and later, and then run `using QuadGK`.
Stacktrace:
 [1] #quadgk#998(::Array{Any,1}, ::Function, ::Function, ::Vararg{Any,N} where N) at ./deprecated.jl:1381
 [2] (::Base.#kw##quadgk)(::Array{Any,1}, ::Base.#quadgk, ::Function, ::Vararg{Any,N} where N) at ./<missing>:0
 [3] macro expansion at /Users/solver/.julia/v0.6/FastGaussQuadrature/test/test_gausslaguerre.jl:40 [inlined]
 [4] anonymous at ./<missing>:?
 [5] include_from_node1(::String) at ./loading.jl:539
 [6] include(::String) at ./sysimg.jl:14
 [7] include_from_node1(::String) at ./loading.jl:539
 [8] include(::String) at ./sysimg.jl:14
 [9] process_options(::Base.JLOptions) at ./client.jl:304
 [10] _start() at ./client.jl:370
while loading /Users/solver/.julia/v0.6/FastGaussQuadrature/test/test_gausslaguerre.jl, in expression starting on line 17

I think the best way would be to hard-code the integral values and remove the dependence on quadgk.

[dlfivefifty]

Some of the changes were to work around the following bug JuliaLang/LinearAlgebra.jl#400

Though I think the changes are for the best anyways (if something is a row vector, it is better to represent it by RowVector).

Note that transpose(vec) no longer allocates new memory, instead, it wraps vec in a RowVector object.

[codecov-io]

Codecov Report

Merging #45 into master will not change coverage.
The diff coverage is 97.72%.

@@           Coverage Diff           @@
##           master      JuliaLang/julia#45   +/-   ##
=======================================
  Coverage   97.72%   97.72%           
=======================================
  Files           8        8           
  Lines        1849     1849           
=======================================
  Hits         1807     1807           
  Misses         42       42

Impacted Files	Coverage Δ
src/besselroots.jl	94.44% <100%> (ø)	✅
src/gaussjacobi.jl	96.1% <100%> (ø)	✅
src/gausshermite.jl	95.71% <100%> (ø)	✅
src/gausslegendre.jl	97.97% <100%> (ø)	✅
src/gausslaguerre.jl	98.48% <60%> (ø)	✅

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[dlfivefifty]

This now works! @ajt60gaibb any objection to merging?

Please join in on the argument in JuliaLang/LinearAlgebra.jl#400 if you have opinions on whether ones(5)*ones(1,6) (vector*matrix) should be a valid operation