Added very simple skeleton for OPML parser and for unittests.
Start work on the read/write functions for OPML files.
Added function, which determine type of outline. Outline can has "rss entry" type or "category" type.
Also I'm added the uncompleted unittest for this function.
And I'm added another different code pieces (for future development).
Rewrite functions, which parse <outer> nodes in OPML file.
Add unit-test for this functions.
Rewrite "low-level" functions (which parse inner <outline> nodes) to make it more simple.
Also, rewrite tests for this functions.
Merge branch 'feature/OPML_parser' of https://github.com/h0rr0rrdrag0n/vt-rss into feature/OPML_parser

fix author's name if previous commits