Gave parallel tests the option of using nice
Added command line option for nice
Updated readme for nice
Removed -n as an option, because it's already used by rspec
Added tests
Add ParallelTests::Cucumber::FailuresLogger to log cucumber failures.

This class subclasess Cucumber::Formatter::Rerun and overrides the 'after_feature' method in order to lock the output file so that multiple processes can write to it.

The output format is similar to cucumber's own rerun output format so it can be re-run with cucumber in the same way. (i.e. by passing the filename to cucumber prefixed with '@', ex: `cucumber @parallel_cucumber_failures.log`).
Refactor ParallelTests::Cucumber::RuntimeLogger to use the new Io module
Update the failure logger to log each cuke failure on a separate line.

(Having each failure on a separate line gives a better indication of the amount of failures and is nicer to read)
Add a spec for the ParallelTests::Cucumber::FailuresLogger.
Update Readme.txt with usage for the cucumber failures logger
Failing test - in Ruby19 workers die when trying to output accented characters
Merge pull request #202 from CDEI/add_cucumber_failures_logger

Added ParallelTests::Cucumber::FailuresLogger to log cucumber failures.
v0.11.2
Thanks Jawwad!
Added a test to make sure that setting nice really results in a lower priority process
Merge pull request #195 from iainbeeston/patch-2

Added an option to execute parallel tests with low priority
Thanks Iain!
v0.11.3
Merge pull request #204 from dawid-sklodowski/bug/ruby-19-workers-die-outputting-accented-characters

Failing test - in Ruby19 workers die when trying to output accented chars
fix test