====== GetCompanyDistribution(college,top) ======
Return the most common companies which are most alumnus of this college work in.

====== Description ======
Given a college name, we can find alumnus of this college are common in which companies.
====== Parameter ======
  - college: college or university name
  - top: the number of top companies
====== Return ======
A sorted list of compayies
====== Detail Information ======
  - given a college
  - find people who were graduated from this college
  - get people information(pid, name, company)
  - map people information to company
  - count the number of each company
  - sort and show top of companies