Enable compression for Tsv, Csv, etc.

Enable compression for delimited scheme outputs. 

> Method setSinkCompression sets the sinkCompression of this TextLine object. If null, compression will remain disabled. 

Cascading automatically disables the compression when sinkCompression set to null.
With sinkCompression set to 'TextLine.Compress.DEFAULT' one can specify the compression on job configuration.
Some Execution fixes
autoload file with user's own custom commands
add 'Config.defaultFrom(mode)', use for replConfig
add test for whether hadoop.tmp.dir is used
Force JobConf to evaluate values in Config.fromHadoop (fixes #1014)
make ReplTest actually run in Hadoop mode again and now just match against the evaluated tmp dir
search up from current directory for '.scalding_repl' files to source
add test to verify that '.scalding_repl' is being loaded
Merge branch 'develop' of https://github.com/twitter/scalding into develop

Conflicts:
	scalding-core/src/main/scala/com/twitter/scalding/FileSource.scala
Update Cascading JDBC Version to 2.5.4.
Merge FileSource.
pipe directly into $SCALD_REPL
refactor InputSizeReducerEstimator to correctly unroll multisourcetaps and improve reporting
fix prettyprint and scalariform
customizable prompt
absolutely superfluous coloring of Scalding splash
Merge pull request #1017 from bholt/bholt/unroll-taps-refactor

Refactor InputSizeReducerEstimator to correctly unroll MultiSourceTaps
explain mysterious '.scalding_repl' file
well that explains why hRaven estimates were backwards