add ad. to Week1_Lecture1.ipynb
a small modification of Week1_Lecture1.ipynb
add ad. to Week1_Lecture2.ipynb
add some information at the top of Week1_Lecture2.ipynb
Revert "add some information at the top of Week1_Lecture2.ipynb"

This reverts commit 63bb51b88d231d5da998f8cc167decba08a7cfaf.
add ad. to Week1_Lecture3.ipynb
add ad. to Week2_Lecture4.ipynb
add ad. to Week2_Lecture5.ipynb
add ad. to Week2_Lecture6.ipynb
add ad. to Week3_Lecture7.ipynb
add ad. to Week3_Lecture8.ipynb
add ad. to Week4*.ipynb
add ad. to try*.ipynb and be*.ipynb
Merge pull request #2 from apua/master

add PyConAPAC ads to notebook