====== updatePerson(pid, information_list, update_date, source) ======
===== Description =====
Update existing person's information

===== Parameters =====
^  Parameter  ^  Necessity  ^  Type  ^  Description  ^
|  pid  |  required  |  int  |  person id  |
|  information_list  |  required  |  list  |  the new information list that need to be added |
|  update_date  |  not required  |  string  |  date when updating the information  |
|  source  |  required  |  string  |  source of the information  |

===== Output =====
Updated person xml files.

===== Implementation =====
  - updateTLNode(): Update timeline node.
  - updateEduNode(): Update education node.
  - createMyTextNode(): Create text content for the node.

===== Related Work =====
XML DOM Tutorial http://www.w3schools.com/dom/