Added test for filtering control charecters from CDATA section of JUnit  formatter output
Added strip_control_chars method in JUnit formatter to strip those chars from the intercepted output of STDOUT and STDERR
spec/cucumber/formatter/junit_spec.rb
 exchanged usage of File to StrinIO and optimized testing of the string with more control chars and only one rule to match them

spec/cucumber/formatter/junit_spec.rb
 optimized the scan call not to include all space chars since it was also matching \f which can cause problems
remove commented dead code
Merge pull request #384 from teacup-on-rockingchair/issue380

fix for issue #380