Add clear fit button to profile window

Closes #431
Join on key
Add Dendrogram Client
Dendrogram widget
State defaults to oldest, not newest, version on restore
Dendro tests
Dendrogram io
Dendrogram documentation
update travis
Dendrogram documentation
Merge pull request #435 from ChrisBeaumont/431

Add clear fit button to profile window
Merge pull request #436 from ChrisBeaumont/dendro2

Dendrograms (updated)
Update travis matrix