removed unnecessary contents, fixed links due to renaming, word wrapped texts

fixed links due to renaming, text wrapped files
Changes from code review.
fixed file links due to rename of js and css scripts
renamed pageLoad.js to page-load.js and modified loadContent function according to changes in try-it-yourself.js
word wrapped contents into 80 chars
moved files into correct directory
added more checkpoint tests for sequence exercise
changed solutions a bit to work, more text-wrapping
fixed link references