Fixes segfault and adds open, creat calls#4

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nkremerh wants to merge 5 commits intodthain:masterfrom

nkremerh:master

Commits on May 11, 2018

Adds open and creat to tracked operations
nkremerh
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Commits on Jun 20, 2018

Fixes segfault issue with calling getenv from other functions
nkremerh
committed

Commits on Feb 13, 2019

Commits on Feb 18, 2019

Adds fopen and freopen
nkremerh
committed