Work on improving event detection with calciumdxdettrial.m
Added dxeventsOptionsDialog guide figure skeleton
Integrated a newly functional dxeventsOptionsDialog script and window into calciumdxevents
Begin fix of calciumdxprefs append save
Finished integration of default detection dialog box and params to dxevents

* Edited all instances of save('calciumdxprefs',… with grep/replacement
to if exist('calciumdxprefs'… for whether or not to create the prefs
file or append
* added dxeventsOptionsDialog.m
* added dxeventsOptionsDialog.fig
* setupDetectionPreferences
* setupDetectionPrefs2Params
Merge branch 'beta'

This adds a new dxeventsOptionsDialog feature to calciumdxevents.
It gives ability to edit default 'normal', 'wave', or 'custom1' parameters as input args to calciumdxdettrial.m event detection.
Minor bug fix of DetectAll and added tooltipstring helpers to dxeventsOptionsDialog
Minor bug fix in saving of calciumdxprefs

Use exist('calciumdxprefs.mat','file') == 2 instead of
exist('calciumdxprefs','file')
Added content to README.md

Edited help doc for #Calcium event detection