Selection Menu prelim

Created a menu for viewing the data of currently selected nodes, also
fixed the splitString method for reading in safe-delineated lines.
Editable Selection Menu

Added textfields to all attributes in selection menu. Need to make edits
change node names in real time.
Completed Basic Selection Menu

Finished work on the right-side selection menu, including scrolling for
attributes and switching between selected nodes.
Centrality and Selection

Added Degree and Closeness centrality coloring and cleaned up the
selection menu scrolling.