added more functions to stock list class

functionality to  add up daily gains and losses and display them
changed UI object label name

changed lineEdit_7 to lineEdit_TodaysGains
changed lineEdit8 to lineEdit_todaysLosses
added getShares() and getOpenPrice() to stock.cpp
added function stubs
adding up user's stock List
changed function names

the function names were too long so i changed them
added "/" to directory path