getBestPlugin: functions available for the host.

* Add C++ files (host/io.*) to get the functions available in C++.
* Bind this in Python, by adding functions in tuttle module.
* Refactoring SWIG file for host/Preferences.
* Update pyTest testGetBestPlugin to fit with the python binding.
getBestPlugin: get only last version of io plugins

Update pyTest testGetBestPlugin.
getBestPlugin: delete python file getBestPlugin

Now available by the python binding.
pyTuttle: no more external python script included
tuttleHost: peanuts, use typedef

Remove unused getPluginsByIDMajor
Merge branch 'dev_addGetBestPlugin' of github.com:tuttleofx/TuttleOFX into develop
pyTuttle: fix examples, getBestReader is now included in the tuttle module
tuttleHost: peanuts, clean include
tuttleHost: loadAndDescribe is already called
tuttleHost: add ThumbnailDiskCache