Fix README

* Fix unpaired quote of -V/--verbose-version
* Remove deprecated -e/--emacs option
* Fix lack of - in -f and -o
* Add -r to the require options
Merge pull request #255 from yujinakayama/fix-readme

Fix README
Add public/private declaration comments
Move Rubocop::Cop::Location definition to offence.rb
Add API documentation of Rubocop::Cop::Location
Hide void return of methods in YARD documentation
Merge pull request #257 from yujinakayama/additional-doc

Additional API documentation
Don't ignore Parser warnings
Differentiate between Parser errors and warnings
Fix a Semicolon cop false positive (fixes #258)
Fix offence sorting

Offences were sorted only by line number, which was problematic when
there were several offences on the same line. Now the column is taken
under consideration as well.
Fix failing spec
Fix bugs in calls to add_offence.

There are a number of places where the location argument to add_offence
is still the line number. It's supposed to be a location object that
responds to line and column. The way to catch these errors in our unit
tests is to access line and column in the Offence constructor.
Print relative paths if the paths are under the working directory

This affects to the simple/progress formatters.
Merge pull request #262 from yujinakayama/print-relative-path

Print relative paths with the simple/progress formatter
Merge pull request #261 from jonas054/fix_location_bug

Fix bugs in calls to add_offence.
Fix code style
Enable self-check of code style
Merge pull request #265 from yujinakayama/fix-style

Fix code style and enable self-check