Updated docs for v 3.1
Added code to change all vertices' icon to human or computer. When computer-style, the type should be autodetermined- mobile, desktop or access point.
More docs, bumped version in POM and help menu is preparation for 3.1 release
Merge pull request #31 from mbatchkarov/master

Master
Merge branch 'manualGui' into develop
Merge remote-tracking branch 'origin/vladi' into vladi
Merge branch 'develop' into vladi
Merge branch 'vladi' into develop

Conflicts:
	src/main/java/view/CustomMouse/CustomPopupPlugin.java
Removed extra line introduced during merge
Changed default background and edge colours when no background image is used
Merge branch 'vladi' into develop

Conflicts:
	src/main/java/model/MyVertex.java
	src/main/java/view/CustomMouse/CustomPopupPlugin.java
Fixed error in merge
Fixed NPE when adding nodes to an empty graph
More error fixes from merge
Some housekeeping
WIP: partial support for saving the predominant icon style when it is changed so that it can be applied if the graph is cleared. Currently this is hardcoded.
Merge branch 'vladi' into develop

Conflicts:
	src/main/java/edu/uci/ics/jung/graph/MyGraph.java
More merge errors
Fixed bug where the type (human/computer) of the vertices in a graph would be lost if the graph is cleared, and then reset to Human by default.
Merge remote-tracking branch 'origin/vladi' into vladi