An ExecutionPlan provides simplified access to the run time behaviors defined by a Convention.
Moved ExecutionEnvironment to main project

Move ExecutionEnvironment to main Fixie project to make it available to
other runners.
Merge pull request #49 from JohnStov/Move-ExecutionEnvironment

Moved ExecutionEnvironment from Fixie.Console to Fixie, so that it can be used by other runners.
Add enum ConstructionFrequency.
ClassBehaviorBuilder exposes a ConstructionFrequency value which describes the convention author's choice of construction frequency.
Rename *PerTestClass to *PerClass, for consistency.
Behavior builder classes collect the custom wrapping behaviors so that they can delay building, and so that the collection of wrapping behaviors can be inspected for diagnostic purposes.
Phase out now-unnecessary initialization call to ClassBehaviorBuilder.CreateInstancePerCase().
Declare array parameter as an IReadOnlyList<T> since the array need not be used as mutable.
Simplify ClassBehaviorBuilder so that the ConstructionFrequency enum can be removed.
Rename members and parameters in ClassBehaviorBuilder for clarity.
ClassBehaviorBuilder no longer combines the choice of construction frequency (per case vs. per class) with the choice of test class factory.
add cli option to opt out of TeamCityListener
Merge pull request #52 from pedroreys/optOutTC

add cli option to opt out of TeamCityListener
Change the new TeamCity command line argument from "--fixie:OptOutTeamCity true" to its inverse, "--fixie:TeamCity off".
CaseBehaviorBuilder.Wrap<TDisposable>() provides shorthand for wrapping all test cases in a new instance of the specified IDisposable type.
InstanceBehaviorBuilder.Wrap<TDisposable>() provides shorthand for wrapping all test class instances in a new instance of the specified IDisposable type.
ClassBehaviorBuilder.Wrap<TDisposable>() provides shorthand for wrapping all test classes in a new instance of the specified IDisposable type.
Rename test methods for consistency.
Simplify case sorting by actually sorting by the array of Case objects rather than sorting the array of CaseExecutions.