Merge pull request #67 from Sergey-Russiyan/develop

Please, review my code. Were added "Logging" chapter.
Implemented validation pages by different strategies, refs: #68
Corrected markdown
Fixed issues found after code review, refs: #68
Merge branch '68_general_page_validator' of github.com:romikoops/howitzer into 68_general_page_validator
Merge pull request #69 from romikoops/68_general_page_validator

Reimplement URL_PATTERN to general page validator
added "Folders structure in RSpec..." section