Added CMakeList modifications to add TextFileReader unit tests to the build, including bumpAllTests.

Modifications add a new unit test target to the Xcode project for the TextFileReader methods. This unit test is also added to the bumpAllTests target. Nothing has been implemented, it is more or less empty, but everything does build.
Added some unit tests for TextFileReader for valid file paths, and different arguments for fileContents methods

Added unit test function for testing both valid and invalid files (testValidityOfFile), reading the entire file (testReadEntireFile), and testing the reading of a subset of the file (testReadSubsetOfFile and testReadFromLineToEnd).