[es5/lambdajs]  Updated main module.
[es5/lambdajs]  Updated main module.

Added a few options to the main module.

-lang (ljs|es5)

 Lets you pick the language to use.  src was split into two variables
 for holding es5 source and ljs source.  This will work up to three or
 four ljs variants.

-pretty (for pretty printing)

-env

 Same as before, but factored out into a fun that does the right thing
 per language.

Now you can have command lines like:

./jsc -lang es5 -js ./test.js -desugar -pretty -env ./es5-env.es5

./jsc -lang ljs -js ./test.js -desugar -pretty -env ./ljs-env.ljs

brownplt/ML-LambdaJS,brownplt/ML-LambdaJS