Remove Exec dependencies and hidden function in __init__ files about qmflows

[felipeZ]

For instances trying to run the following command:

nosetests test --with-coverage --cover-erase --cover-package=qmworks --cover-xm -v   

Run all the test correctly, but generates the plams output for all the test files in the examples\Constrained_and_TS_optimizations
Because the tests scripts are linked to the examples and the first test to call the run method set the CWD as the plams default folder.

[ridderl]

I designed the examples such that they don't need to read files from the example folders. As a result the tests don't need to change the cwd, solving this issue.

If you are happy with this solution please close the issue :-)