Moved the features for changing layout, changing roundness of edges, refreshing layout placement to the popup window for customize. Also adjusted tree layout.

Added validation check for diff_sets and diff_nets to check first if the same two networks area chosen.

Merge branch 'master' of https://git.wur.nl/rocherno.dejongh/netshiny

# Conflicts:
#	helper_functions.R
#	main.R

Adjusted code such that a combination of dataframes and matrices can also be passed as arguments for the Net.obj argument