Msprime

**Bug fixes**:

- Fix (very) rare assertion trip caused by underlying GSL bug.
({issue}`1997`, {pr}`2000`, {user}`chriscrsmith`, {user}`molpopgen`,
{user}`andrewkern`)

**Maintenance**:

- Various documentation improvements.

**New features**

- Add support for tree sequence ``time_units`` field. The ``time_units`` will
be set to "generations" for the output of ``sim_ancestry`` (and ``simulate``),
unless the ``initial_state`` argument is used. In this case, the
``time_units`` value will be inherited from the input.
({pr}`1953`, {issue}`1951`, {issue}`1877`, {issue}`1948`, {user}`jeromekelleher`).

**Bug fixes**:

- Raise an error if `Demography.from_demes()` is passed a model
with non-zero `selfing_rate` or `cloning_rate` values (which msprime
does not support).
({pr}`1938`, {issue}`1937`, {user}`grahamgower`).

- Do not assume Population metadata schemas contain the ``properties``
and ``additionalProperties`` attributes ({issue}`1947`, {pr}`1954`,
{user}`jeromekelleher`).

- Read the population name from PopulationConfiguration ``metadata`` in
``Demography.from_old_style`` ({issue}`1950`, {pr}`1954`,
{user}`jeromekelleher`)

**Maintenance**:

- Update tskit to Python 0.4.0 and C 0.99.15.

**New features**:

- Support for Demes 0.2.0, which introduces a change to how pulse
sources and proportions are specified.
({pr}`1936`, {issue}`1930`, {user}`apragsdale`)

This is a bugfix release recommended for all users.

**New features**:

- Support for running full ARG simulations with gene conversion
({pr}`1801`, {issue}`1773`, {user}`JereKoskela`).

- Improved performance when running many small simulations
({pr}`1909`, {user}`jeromekelleher`.)

- Update to tskit C API 0.99.14 ({pr}`1829`).

**Bug fixes**:

- Fix bug in full ARG simulation with missing regions of the genome,
where ARG nodes were not correctly returned. ({issue}`1893`,
{user}`jeromekelleher`, {user}`hyl317`)

- Fix memory leak when running ``sim_ancestry`` in a loop
({pr}`1904`, {issue}`1899`, {user}`jeromekelleher`, {user}`grahamgower`).

- Fix printing small values in rate maps ({pr}`1906`, {issue}`1905`,
{user}`petrelharp`).

Improved Demes support and minor bugfixes.

**New features**:

- Support for Demes input and logging in the msp simulate CLI
({pr}`1716`, {user}`jeromekelleher`).
- Add ``Demography.to_demes`` method for creating a Demes demographic model
from an msprime demography ({pr}`1724`, {user}`grahamgower`).
- Improved mapping of Demes models to Demography objects
({pr}`1758`, {pr}`1757`, {pr}`1756` {user}`apragsdale`).
- Improved numerical algorithms in DemographyDebugger ({pr}`1788`,
{user}`grahamgower`, {user}`petrelharp`).

**Bugfixes**:

- Raise an error if running full ARG simulations with gene conversion
({issue}`1774`).

Minor feature release with experimental Demes support.

- Change the semantics of Admixture events slightly so that ancestral
populations that are inactive, are marked as active ({pr}`1662`,
{issue}`1657`, {user}`jeromekelleher`, {user}`apragsdale`)

- Initial support for Demes via the ``Demography.from_demes`` method.
({pr}`1662`, {issue}`1675`, {user}`jeromekelleher`, {user}`apragsdale`)