Dvha

--------------------
- [Database Connection] Initialize SQL tables upon successful new database connection
- [Database Connection] Catch invalid SQL credentials at launch, automatically open connection settings dialog
- [DICOM Importer] Display PTV ROI type in RT Structure tree. Helpful for multi- PTV plans.
- [DICOM Importer] Set force=True with pydicom.read_file() for XiO support [issue 15](https://github.com/cutright/DVH-Analytics/issues/15)
- [DICOM Importer] Apply fix for TransferSyntaxUID error [issue 16](https://github.com/cutright/DVH-Analytics/issues/16)
- [Query] Added a catch and error dialog for a MemoryError when querying if users queries more data than their system can handle

--------------------
- [Machine Learning] More visual options available in settings
- [Plot Visuals] Hover information pop-ups display with data only. Trends, stats, etc. no longer clutter
- [Stats Data] Spreadsheet class created, used to display Stats data with ability to edit.
This means you can add custom numerical data for trending, regressions, machine learning.
- [Misc] All data, multi-variable regression, and machine learning windows close when main window is closed

--------------------
- [Control Chart] Adjusted Control Charts automatically populated from Regressions tab after running model
- [Machine Learning] Redesigned PlotRandomForest class to PlotMachineLearning to support Random Forest, Decision Tree,
Gradient Boost, and Support Vector Machine
- [Machine Learning] Modules redesigned to allow for complete input parameter customization
- [Machine Learning] Modules allow for data splitting (training and testing)
- [Machine Learning] Models can be saved to a pickle file, their use not yet implemented
- [Regression] Run all regressions on run

--------------------
DVH Analytics has been completely rewritten using the wxPython Phoenix framework.
- Tested on Mac OS Mojave, Windows 7, and Linux.
- No longer depends on launching bokeh servers
- PostgreSQL database is still needed and is in largely the same format as before (new columns added)
- Modeling with Random Forest has been added, other algorithms coming soon
- Control Charts and Adjusted Control Charts have been added
- Currently only one query group is allowed, 2nd group will come in a future version
- DICOM files are properly connected with SOPInstanceUIDs rather than just StudyInstanceUIDs
- Multiple plans connected by the same StudyInstanceUID will have their dose grids automatically summed
- WARNING: this assumes your dose grids are aligned, interpolation for non-aligned grids coming soon

* Bug fix in dvhs.py causing crash due to syntax typo on lines 318 and 429

* Allow roi_name in query