Add serialization of graphical configuration

[mortbopet]

It should be possible to store and load a file for specifying the configuration of the graphical view. Serialized data should include:

• Component positions
• Component expansion state
• Component sizes
• Component routing regions

Serialization of wires will come in a later stage, when place/route is fully implemented. Serialization should be facilitated by a common library, such as:

• Boost serialize https://www.boost.org/doc/libs/1_69_0/libs/serialization/doc/index.html
• Cereal https://uscilab.github.io/cereal/