Dec29

@leapfrog-dipendra  @adhpawal  @bhuwang  @anishmanandhar  @Satish-Gupta  @nerisa  @utsabneupane 
Function name displayDivisibleRange does not display the divisible range instead it returns the sum of the numbers divisible by 7. Function name returnSumDivisibleBySeven will be the better name for that function. You can still debate to find the better name.