Update dependency
Merge branch 'master' of https://github.com/alexandrebouchard/conifer
Fix #13
Add clade and metric features
Add test for generation of unrooted trees
Fix dependency update needed in the other commits sent today
Fix #14
Problem detected

TestSimplePhyloModel fails. Unclear when this got broken (many recent
changes seem to have been pushed without running the test suite).
Prototype of new SPR move seems to pass tests now
Clean up new SPR code
Clean up various other comments created during debugging
Move some documentation from conifer to bayonet
More explicit error when TreeNode description is null
More explicit error message for non-unique leaves and missing branch len
Improve grammar for parsing trees

- use a simplified grammar
- number should not start by E/e (o.w. could be confused to node name)
- taxa name should not start by -/number (o.w. could be confused to len)

Fix #16
Add test for tree parser
Fix dependency of previous commits of today
Fix #17
Clean-up TestGenerateUnrooted

Note: the test might be at the boundary of failing, inspect and adjust
later if problem arises again
Improve doc on tree parser