Add notes for first lecture
Partial cleanup of main text

No content is changed in this commit; it just replaces some of
the description lists in the intro text to a defninition
environment.
Remove R lecture file -- same code is in md
Edits to ARMA material
Tweak acronyms in preamble
Merge 'intro' branch

This branch moves the introductory ARMA modeling material into the
main part of the text"
Bump version to 0.2.2
IJulia notebook for VAR normality and forecasting lecture
Bump version
Add license information to VAR notebook and bump version
Start IJulia notebook for SVAR lecture
Add short and long run restrictions lectures
Add partial-identification to SVAR notes
Tweak lecture notes immediately before an dafter lecture
Merge branch 'svar_lecture'

Adds IJulia notebook for notes on structural vector autoregressions
Bump version to 0.2.5
Merge branch 'master' into bayes