Bugfix release

[1.0.3] - 2021-11-12

This is a bugfix release recommended for all users.

New features:

• Support for running full ARG simulations with gene conversion (#1801, #1773, @JereKoskela).
• Improved performance when running many small simulations (#1909, @jeromekelleher).
• Update to tskit C API 0.99.14 (#1829).

Bug fixes:

• Fix bug in full ARG simulation with missing regions of the genome, where ARG nodes were not correctly returned. (#1893, @jeromekelleher, @hyl317)
• Fix memory leak when running sim_ancestry in a loop (#1904, #1899, @jeromekelleher, @grahamgower).
• Fix printing small values in rate maps (#1906, #1905, @petrelharp).