minor stability improvements

v1.4.5

Merge branch 'master' of https://github.com/JingningShi/MtreeRing

1.4.2

MtreeRing 1.4.2 (2019-10-03)

• Update GitHub links in ring_app_launch function

v1.4.0

MtreeRing 1.4.0 (2019-09-01)

• Redesign the interface and measurement process for the Shiny app
• Update documentation for the redesigned Shiny app
• Add a Support section in the README file
• Replace all vignettes with GitHub links