Coverage for 0.11 new features + README updates for TextMate 2 users

Tested using the following code:

-- RANK (and DENSE)
A = load 'data' AS (f1:chararray,f2:int,f3:chararray);
C = RANK A by f1 DESC, f2 ASC DENSE;


-- CUBE and ROLLUP
events = LOAD '/logs/events' USING EventLoader() AS (lang, country, app_id, event_id, total);
eventcube = CUBE events BY CUBE(lang, country), ROLLUP(app_id, event_id);
result = FOREACH eventcube GENERATE FLATTEN(group) as (lang, country, app_id, event_id), COUNT_STAR(cube), SUM(cube.total);
STORE result INTO 'cuberesult';


-- datetime
A = load 'datatypes' AS (f1:chararray, f2:int, f3:long, f4:float, f5:datetime, f6:double, f7:bytearray, f8:boolean, f9:tuple, f10:bag, f11:map);


See http://blog.cloudera.com/blog/2013/02/apache-pig-it-goes-to-0-11/ for the non-exhaustive list of new keywords. I'm sure we can ask Bill/Dmitriy if we missed any.

For some reason it is really difficult in Textmate 2 to reload plugins, I will check with Macromate on that point.