Bug fixes and linear interpolation

v2.2.0

iif

number interpolates don't allocate, updated Rosenbrock

v2.1.0

diff_type

Get rid of warning

v2.0.3

Update REQUIRE

Interpolation patches

Merge pull request #44 from tkelman/iteratorsfix

Compat.Iterators needs 0.18 minimum

v0.6 depwarn fixes

v2.0.1

final depwarn fix?

Compatibility with refined ODE problems

v2.0.0

fix for constant transfer

Update for DiffEqBase v0.15.0

v1.8.0

no double copy

SSPRK and safer dense

v1.7.0

throw error if early number

Fix out of place on v0.6

v0.6 needs more broadcast. Fine.

Retcodes and Callback Initialize

v1.6.0

Update REQUIRE