Issue #160: Support rerun file with failed features/scenarios during the last test run

* NEW: RerunFormatter, generates features configfile with
  scenario file locations of failed scenarios during the test run.
* Support file locations now that select a scenario in a feature on command line
* If a file location is used:
  automatically select additional scenarios that have @setup/@teardown tags.
* Merge multiple adjacent file locations to the same feature file together.
* Refactor common runner parts into behave.runner_util
  (reduces codes of behave.runner, too)
* Refactor, relocate: runner => runner_util
  parse_features_configfile()
  feature_files()
  parse_features
  make_undefined_step_snippet()
* model.Feature: Added walk_scenarios() to simplify processing flat list.
* model.Feature, Scenario: Added should_run() that implements the run decision logic.
* model.Feature, Scenario: Rename should_run_with() => should_run_with_tags()
Update changes with info related to issue #160
Raise FileNotFoundError if feature configfile does not exist.
FIX issue #153: model/runner should not misuse formatters.
Mark filters/filter_formatter as DEAD, BROKEN.
* INCOMPATIBLE CHANGE: Formatter Ctor uses now StreamOpener instead of Stream.
  Formatter output streams are now opened late, under control of the formatter.
  This allows the formatter also support directory mode (if needed).
  Needed for RerunFormatter whose file was overwritten before it was read.

* NEW: TagCountFormatter, TagLocationFormatter (reenabled and implemented)
* ProgressFormatter: Flushes now output to provide better feedback.
* issue #153: The runtime should not by-pass the formatter to print line breaks minor
Update w/ latest changes.
Finished feature rerun.
Use RerunFormatter by default.
Add tests and self-tests related to new functionality (related to #160 and more):

  * Selection of scenarios by file locations.
  * RerunFormatter
  * TagCountFormatter
  * TagLocationFormatter
Correct test after changing the core logic of tag count collection.