MOcov/MOcov

…cause Matlab raises an error when trying to write to fid=0

For now helper functions for classdef syntax check do not
need to be shared, so them can go back to the test file itself.

Tempfolder usage can be avoided to make test simpler.

Additionally make whitespace consistent in test file.

OBS: The function name assertSringContains was written using
camelCase to be consistent with MOxUnit assertion helpers.

Avoid prepending `mocov_line_covered` to:

- `classdef`;
- `properties` and `methods` section opening statements;
- inside the entire `properties` section, since a limited subset of the
  M-file syntax is allowed.