Relevant comments are in #2062.

- use lud and lud! methods for the decomposition
- allocate umf_conf and umf_info and use them throughout
- preserve the pointers to the symbolic and numeric factorizations in
  the UmfpackLU object.  Also keep around the decremented
  index/pointer vectors.

…and qrpd.

Update docs for qr.

Conflicts:
	base/deprecated.jl
	test/Makefile

…g by defining a Julia type

Well, working on a 64-bit system and these are only the calls to
cholmod_check_dense and cholmod_print_dense, as in

julia> aa = randn(10,2)
10x2 Float64 Array:
 -1.1131     -0.276926
 -1.18138    -2.17424
  0.615017   -0.341257
  0.0714101  -0.0933698
 -0.493773   -0.520607
  0.989568   -0.0106482
  1.33313    -0.204813
 -0.199893   -0.983869
  0.934582   -0.0652311
  0.792507   -0.369899

julia> cda = CholmodDense(aa)
CholmodDense{Float64}(10,2,20,10,Ptr{Float64} @0x0000000003186070,Ptr{Void} @0x0000000000000000,1,0,10x2 Float64 Array:
 -1.1131     -0.276926
 -1.18138    -2.17424
  0.615017   -0.341257
  0.0714101  -0.0933698
 -0.493773   -0.520607
  0.989568   -0.0106482
  1.33313    -0.204813
 -0.199893   -0.983869
  0.934582   -0.0652311
  0.792507   -0.369899 ,false)

julia> SuiteSparse.chm_chk_dn(cda)
1

julia> SuiteSparse.chm_prt_dn(cda)

CHOLMOD dense:   :  10-by-2,
  leading dimension 10, nzmax 20, real, double
  col 0:
         0: -1.1131
         1: -1.1814
         2: 0.61502
         3: 0.07141
         4: -0.49377
         5: 0.98957
         6: 1.3331
         7: -0.19989
    ...
  col 1:
         0: -0.27693
         1: -2.1742
         2: -0.34126
         3: -0.09337
    ...
         6: -0.20481
         7: -0.98387
         8: -0.065231
         9: -0.3699
  OK

4-element Uint8 Array:
 0x03
 0x00
 0x00
 0x00

Not exactly earth-shattering but at least it is a proof-of-concept for
using a Julia type to pass a pointer to a struct to one of the CHOLMOD
functions.

but my external constructor from a SparseMatrix{Tv,Ti} is not working
as hoped.  I'm pushing this commit in case someone can try
```julia
require("suitesparse")
using SuiteSparse
A = sprand(8,4,0.25);
ca = CholmodSparse(A)
```
and tell me why I get a no method error.

Defined types c_CholmodDense which mirrors the cholmod_dense C struct and a wrapper
type CholmodDense that retains the Julia matrix when constructed from one and retains
the pointer itself when constructed from *cholmod_dense returned from C.

Still need to add a finalizer for the CholmodDense type and create
similar types for CholmodSparse, CholmodFactor and CholmodTriplet.