Igors assignment

[IgorTurko]

DONE:

• getData implemented;
• USER_TOKEN authentication type replaced with NONE;
• postLimit multiple selector replaced with single selector;
• some refactoring for getSchema;

NOT DONE:

• Need to investigate if we can use AuthType.USER_TOKEN instead of AuthType.NONE;
• at the moment we are fetching only posts from the first page (so max 100), that means the the postLimit filter won't work with more than 100 posts;