* Update file "index.md"
added text = 'aka Parent Node'
increased branch length from the root
* text replaced in index.md file
text 'aka' replaced with 'also known as' in index.md file
* Translate challenge subtitles and example challenge text to Spanish
* Corrected errors in syntax and punctuation
* Multiple corrections of it/s to its plus other grammar corrections
* Correction and added paragraph to CSS Flex article
* Corrected my own typo
* Corrected capitalization, American spellings and typos
* Update index.md by fixing typos
Also, added section for learning about Depth-first searching and Breadth-first searching.
* Update index.md - reverting back to original verbiage.
