Added Stack#14

Merged

czgdp1807 merged 9 commits intocodezonediitj:masterfrom

czgdp1807:stack

Jun 25, 2019

Commits on Jun 21, 2019

Added Stack data structure, tests remaining
Kartikei-12
committed

Commits on Jun 22, 2019

Added tests for Stack data structure and reformatted docstrings according to numpy doc format
Kartikei-12
committed
Rectified simple typo and made code capatible for python 2.7
Kartikei-12
committed
Rectified strip function with replace correct logic
Kartikei-12
committed

Commits on Jun 24, 2019

Commits on Jun 25, 2019