CHOP-60. Fix the script tests so that they run in hadoop local mode.

Add a method to the ScriptRunnerSuite that modifies the classpath of the System
classloader. The reason for this horrible hack is because the classes produced
by the Eval package when compiling the script lives in a separate classloader
and hence when the M/R job is launched in local mode, Cascading can't find these
classes unless the folder containing the compiled classes is added to the
classpath.

Reviewed by: robert
CHOP-70. Deprecate the need for the EXPRESS_CLASSPATH variable.

Currently when specifying any third-party dependencies (job jar, dependency
jars etc) when running the express command, the user must set the
EXPRESS_CLASSPATH variable ahead of time. Now that variable is deprecated in
favor of a command line option (--libjars) where the user can specify a colon
separated list of dependency jars.

Reviewed by: robert, kiyan
CHOP-70. Fix a quoting bug in the express script

Now passing in a value with a glob character to the
--libjars argument works.

Reviewed by: kiyan