PARQUET-84: Avoid reading rowgroup metadata in memory on the client side.

This will improve reading big datasets with a large schema (thousands of columns)
Instead rowgroup metadata can be read in the tasks where each tasks reads only the metadata of the file it's reading

Author: julien <julien@twitter.com>

Closes #45 from julienledem/skip_reading_row_groups and squashes the following commits:

ccdd08c [julien] fix parquet-hive
24a2050 [julien] Merge branch 'master' into skip_reading_row_groups
3d7e35a [julien] adress review feedback
5b6bd1b [julien] more tests
323d254 [julien] sdd unit tests
f599259 [julien] review feedback
fb11f02 [julien] fix backward compatibility check
2c20b46 [julien] cleanup readFooters methods
3da37d8 [julien] fix read summary
ab95a45 [julien] cleanup
4d16df3 [julien] implement task side metadata
9bb8059 [julien] first stab at integrating skipping row groups