Fix NLsolve compatibility

Merge pull request #217 from devmotion/nlsolve

NLsolve update

DAE initial dt handling.

v2.21.2

catch bad initdt

Fix eps for floating point handling

v2.21.1

Merge remote-tracking branch 'origin/master'

DiffEqBase 2.0.0 compatibility

v2.21.0

require diffeqbase 2.0.0

Allow initialization to set the starting value and save

v2.20.0

Merge remote-tracking branch 'origin/master'

Some more bugfixes

v2.19.1

Merge remote-tracking branch 'origin/master'

New SSPRK and changes for state-dependent delays

Merge pull request #186 from devmotion/dde_updates

Add support for AbstractContinuousCallback and arbitrary discontinuities

New RKN, SSPRK, cache fixes for stiff DDE, MidpointSplitting

Merge pull request #176 from devmotion/fix_forwarddiff_interpolant

Enable autodifferentiation of in-place interpolants

DiffEqDevTools, high order RKN, ImplicitMidpoint, Exponential RKs

Merge pull request #164 from devmotion/sdirk_update

WIP: Update of SDIRK and generic implicit integrators

Export OrdinaryDiffEqAlgorithm again

Too many people relied on this for dispatch it seems. And this releases a few RKN solvers.