Implemented ini-style config reading

* "tangelo" section: most settings

* "girder" section: girder api mounting settings

* "vtkweb" section: vtkweb integration settings
Improved config file handling

* specific errors are reported

* "interpolation" style config parser not being used (keep things simple)
Fixing typo in error report
Better startup logging
Simplifying config file handling.

Default search no longer happens.  If a file is not specified with
the -c switch, then just the defaults will be used.
Fixing error in setup.py
Fixing error in test runner

Adding better error reporting mechanism to test runner
Fixing label issue in docs
Fixing "missing tangelo.ico" warning
Updating docs
Merge pull request #381 from Kitware/config-ini

ini style config files

Closes #363
Closes #369