jharwell/sierra: Development release 1.5.14-beta

Commits

• e4fe637: enh(#405): --expdef plugin improvements (John Harwell)
• 04fc1f9: feature(#408): Histogram graph (John Harwell)
• 5a382e5: enh(#411): Improve graph comparison plugin (John Harwell)
• ec528b6: enh(#412): Multi-file collation (John Harwell)
• 84c2cce: feature(#415): 2D scatterplot (John Harwell)
• 738da99: docs(#409): Update bokeh plots (John Harwell)
• addbb74: Address #373, #372 (John Harwell)
• 51e0dcd: Address #373, #372 (John Harwell)
• efcdab5: test(#371): Move to actual PBS test (John Harwell)
• f305740: enh(#419): More stat kernels (John Harwell)