Implement simple population model

[Dvorkam]

Simple population model will work via two directly connected relationships ie.:

• Populations the population consumes
• Populations the population is being consumbed by

It will address the issue of capacity of given area, the immigration and emigration

• [ ] Implement general population class
• [ ] Implement time mechanism
• [ ] Population model actual
• [ ] Implement simple text viewer to see population changes
• [ ] Save output to file