Add gtest files

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>
Integrate gtest to sort dir Makefile

The tests will be in the tests directory.
No useful test is written in the sorttest.cpp atm.

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>
Add basic test, impl getVect & setVect in SortBase

The basic test was added just to check if gtest works

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>