Fix some tests that were failing on Linux
Fix some tests that were failing on Linux

Also refactor the code to use a single method for obtaining the execution
folder from the running assembly.  This was involved in all three test
failures.

BloomBooks/BloomDesktop,BloomBooks/BloomDesktop,JohnThomson/BloomDesktop,gmartin7/myBloomFork,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,gmartin7/myBloomFork,andrew-polk/BloomDesktop,andrew-polk/BloomDesktop,andrew-polk/BloomDesktop,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,gmartin7/myBloomFork,gmartin7/myBloomFork,JohnThomson/BloomDesktop,BloomBooks/BloomDesktop,JohnThomson/BloomDesktop,gmartin7/myBloomFork,StephenMcConnel/BloomDesktop,andrew-polk/BloomDesktop,JohnThomson/BloomDesktop,andrew-polk/BloomDesktop,StephenMcConnel/BloomDesktop,BloomBooks/BloomDesktop,andrew-polk/BloomDesktop,StephenMcConnel/BloomDesktop,gmartin7/myBloomFork,JohnThomson/BloomDesktop,StephenMcConnel/BloomDesktop