preserve sparsity when transforming ineqconicproblem to conicproblem
First few files of the refactor, with Madeleine's dcp calculus.
typos in constraints.jl
moved minus signs in multiply_divide for 3-4x speed improvement
Merge branch 'refactor' of github.com:cvxgrp/CVX.jl into dev
Merge branch 'dev' of https://github.com/cvxgrp/CVX.jl into refactor
madeleine adds cone forms and fixes some typos
Merge branch 'refactor' of https://github.com/cvxgrp/CVX.jl into refactor

Conflicts:
	src/problems/conicproblem.jl
added dual_conic_form for refactor
Fixed minor bugs and typos. dual conic form for addition seems to mostly work now
Merge branch 'dev' of https://github.com/cvxgrp/CVX.jl into refactor

Conflicts:
	src/atoms/affine/multiply_divide.jl
Added problems and code to transform problem to dual_conic_form
fixed some bugs in converting problem to dual conic problem.
Add basic MPB interface to refactored
add basic comments/cleanup
added convenience method minimize, etc. renamed modeul in refactored folder to CVX
Merge branch 'refactor' of github.com:cvxgrp/CVX.jl into refactor
dual conic form for multiply atom. rename NoVexity to NotDcp
Merge branch 'refactor' of https://github.com/cvxgrp/CVX.jl into refactor

Conflicts:
	refactored/dcp.jl
	refactored/multiply_divide.jl
added sign constraints