Google Drive API support

[Vasar007]

Changes list:

• Remove API key from code & fix class filename;
• Fix interface incorrectness;
• Add InputManager;
• Encapsulate some data (change access modifiers);
• Add support for download and read common files from google drive;
• Rework file work;
• Fix minor bugs;
• Fix inconsistent with Google API parameter names in reflection class;
• Fixed disposing of memory streams;
• Add OutputManager and LocalFileWriter;
• Change result type from appraisers;
• Add more abstractions for intputters and outputters;
• Use range algorithm instead of foreach approach;
• Add HelperMethods class and null checks;
• Unify null checks with operator is;
• Refactor Google Drive Workers hierarchy;
• Add feature to clean created temporary files;
• Add create and update methods to ineract with Google Drive API.

Closing issues

Closes #3;
Closes #7.