Print a stack trace when the interpreter sees an exception.

Set the process.exit code to 8 on error
Fixes #812

Reviewed on #814.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/823

Closes #823, closes #812.
Simplify the ErrorReporter to not support rest params

The usage of rest params is less useful now that we have full support for template literals.

Review URL: https://github.com/google/traceur-compiler/pull/821

Closes #821
CPS transformer: Extract the variable hoisting

Move the variable hoisting out of CPSTransformer into its own transformer. Then let the CPSTransformer hook into that for its machine generated variables.

Review URL: https://api.github.com/repos/google/traceur-compiler/issues/817

Closes #817.