Initial commit for skills2
Implemented first two functions (building a histogram for a string and for a file).
 Implemented the two 'find common items' functions, the 'find pairs that sum to zero' function, and the 'find duplicates' function.
Partially implemented word_length function; still not working.
Merge branch 'master' of https://github.com/doubledherin/hackbright_skills.assessment