Add fixStack method

- Before sending a query to the server we use a dummy stack container
  to get the current stack trace and store it in the closure
- When a query has an error this method can be used to replace the
  current stacktrace with the stacktrace from the closure
- At the same time the first line in the stack trace ([object Object])
  will be replaced with the actual exception name and message
- The stack trace at the point where the error is discovered only
  contains references to node-cassandra-cql and is therefore not
  helpful for the user to figure out which part of his own code caused
  the error
Save stacktrace before sending query

- Save the stacktrace on the way down into the call stack and restore
  it to eventual errors on the way back out to the caller
Added build image
Merge branch 'query_and_stack_on_errors' of https://github.com/sgronblo/node-cassandra-cql into query_and_stack_on_errors
Appended original stack trace before tick
Added contributor
Merge branch 'master' into resultemitter

Conflicts:
	index.js