Update series.tex

Line 491 (page 50 Example 2.4.1 -- telescoping series) : 
added '+' between '\frac{1}{1+1} and \frac{1}{2}' (following request on forum, thread_id=205).
Merge pull request #15 from AlmeCap/Textbook-Series

Update series.tex
Fixed mispointed reference
Merge branch 'master' of github.com:kisonecat/sequences-and-series
Wrong bounds
Add video link to evaluateGeometricSeriesFraction

Add link to video for the second question of the Week 2 Homework.
fixes #016
Added list of videos for each week
Video titles for week 3
Looking at the logistic map in sage
Fixed resolution
Some approximations for the Stirling formula lecture
Final draft of root test section
Still would like to rewrite part of the ratio test proof
Draft of textbook for week 3
Fix typo: smaller -> small.
Fix typo: ...is [to] think....
Reflow nth term test warning.

This is a perhaps more readable alternative than the hanging side note
after the warning block.
Fixed typo: because -> being.
Fixed a couple of example/solution typos.
Fixed type: we shown -> we've shown.