Hotfix complex numbers initial dt

There was a bug introduced due to units handling that caused the unitless norm of complex numbers to be complex, causing an error in initial dt comparisons. This hotfix fixes that specific issue, and is being put out quickly since two issues immediately opened for it!

Test solution bug fix

Fixes DiffEqDevTools and DelayDiffEq's tests

ApproxFunDiffEq Ready

Movement of certain constant function declarations.

Steady State Solution Hotfix

Needed for SteadyStateDiffEq.jl tests to pass for its registration.

DAE Hotfix

Error in the type ordering for DAEs found by Sundial's tests. Tests still fail until OrdinaryDiffEq and StochasticDiffEq update, but this change is what's needed for Sundials tests to pass (locally checked)

Stable Release

This marks the end of the restructuring changes. This means it includes the change of the solution type to AbstractVectorOfArray, moves out the noise processes and uses the new noise process interface, adds the "refined" problem types, adds mass matrices, finalizes the callback interface, finalizes the linear/nonlinear interface, and throws in some general patches. This is marked as stable as these have been in the list of changes since the beginning, and now are complete. The only other known future changes are

• linear operator types
• problem conversions/promotions

The first is a new future related to PDEs and thus it's DifferentialEquations 3.0 material, and will be non-invasive to add. Problem conversions/promotions would be nice, but not a priority right now so maybe 3.0 material. Should be non-disruptive too when that finally comes. So this sounds like a good stable place to set 1.0.0!

API Overhaul

RODEs
NoiseProcess integrators
No test problems
Analytic definitions
EulerHeun and RKMil interpretation
noise_rate_prototype and noise_prototype
save_everystep
saveat number
save indices
save_start
saveat -> no everystep
Callbacks in problems

Function plotting, MonteCarloProblem, Parameter Interface

v0.14.0

Move out Monte Solve

Retcodes and Callback Initialize

v0.13.0

implement retcodes

Patch 32-bit

32-bit usage of DEDataArrays was broken by a hardcoded Int64. It is changed to Int, which should fix OrdinaryDiffEq.jl's 32-bit tests.