Dvha

--------------------
- [Correlation] Catch crash if there is insufficient data for a correlation calculation
- [Modeling] Allow user to load saved models (Multi-Variable and Machine Learning)
Still under development, currently ML must be loaded after a MVR has been generated
- [Query] Fix for [issue 20](https://github.com/cutright/DVH-Analytics/issues/20)
- [Query] Corrected physician count of query
- [Executable] Initial version with MS Windows executable available

--------------------
- [DICOM Importer] Fix for [issue 30](https://github.com/cutright/DVH-Analytics/issues/30)
- [Machine Learning] Fix for [issue 29](https://github.com/cutright/DVH-Analytics/issues/29)
- [Misc] LICENSE was renamed to LICENSE.txt in v0.6.7, but MANIFEST.in and paths.LICENSE_PATH were not updated
- [Multi-Variable Regression] Added "Backward Elimination" button to automatically remove insignificant
variables using backward elimination

--------------------
- [Database] SQLite3 is now supported
- [Database Connection] The last successful SQL connections settings are stored for easy reload
- [DICOM Importer] Auto assign ROI type physician_roi name is gtv, ctv, itv, or ptv
- [DICOM Importer] Allow import dialog to close on crash
- [DICOM Importer] Sometimes sim_study_date and birth_date were not date objects, more robust age calculator to account for this

--------------------
- [About] Fix bug that displayed version of last options save instead of currently installed version
- [Endpoints] ensure extra_column_data values do not have commas, issue [20](https://github.com/cutright/DVH-Analytics/issues/20)
- [Time Series] Prevent crash if simulation date is not able to be parsed by dateutil

--------------------
- [Correlation] New tab added showing a correlation matrix
- [Database Editor] Fix for GH Issue 19
- [DICOM Importer] Fix for GH Issue 18
- [DICOM Importer] Added Save ROI Map button, Importing actually saves ROI map now
- [Export] Fixed a bug that would not export DVHs Summary without also exporting DVHs
- [Export] Fixed a bug when exporting RadBio data, could crash when writing gamma ('\u03b3')
- [Machine Learning] Mean-square error prints in scientific notation if not between 1 and 1000
- [Query] DVH bin width may be set. SQL still stores 1cGy bin widths, but query will keep dvh data
using specified bin width. This results in faster bokeh plot generation.
- [Query] Query Groups are back!
- [Regressions] Bug fix when removing None and NaN data
- [Regressions] MS Windows only, if multiple dependent variables were defined, each new view displayed the same bokeh
layout. The following Machine Learning windows had the correct data. Fixed by including dependent variable name
html file name for multi-variable_regression. Did not affect other OSs because html files are stored only for MSW.
- [Regressions] Catch error on multi-variable regression, print error to dialog window
- [User Options] Fixed bug that did not restore saved options after clicking cancel

--------------------
Skipped due to PyPi / setup tools issues.