Expand from stage structured to age classes

In order to look at the age distribution and how it changes through
time, I'm going to split out the stages into annual age categories up to
age = 20y.
Now with age structure and demographic stochasiticity
Now includes the shiny app for a demographically stochastic model. Deleted the "all Stoch..." models because they were just copies of the DemStoch models with no additions.
making it a tabbed interface

fixed the age dist axis
reran the knit to html
Merge pull request #1 from paulchafeecross/Age-Structured

Age structured