updated readme
updated readme
renamed source filenames & added zip
corrected errors in exercise 4
finished Ch3_Ex2
modified .gitignore
finished Ch3_Ex6
finished Ch3_Ex13 & modified Ex2 & Ex6
added Chapter3 zip
Merge branch 'release/Ch3_Finished'
fixed missing price implementation
fixed Ch3 zip
Merge branch 'release/Ch3_Finished_v2'