Confirm with user before creating a new database or collection on mongo

IGV-2020
Give better error message when genome can't be downloaded (give full path)
Add ability to query features by name. No automatic index creation for that field, it may not be super-efficient

IGV-2020
Lookup feature by token instead of whole search string in SearchCommand (that was probably an oversight)

Add API hook for adding feature searcher. Not used yet, planning on implementing for Mongo
Save setting for Filter Secondary Alignments as set in preferences
Allow registering a custom searcher by feature name

Refactor so our inexact feature search is performed this way
Feature searching registration cleanups

Added unit tests for searching for features in MongoDB
Remove org.broad.igv.graph package as it is unused
Add unit tests for registering/unregistering SearchCommand name searcher
Limit search results for FeatureNameSearcher
Have tests reset FeatureSearchers
Change FeatureNameSearcher -> NamedFeatureSearcher
Better error handling in RuntimeUtils
Merge remote-tracking branch: upstream/master