PARQUET-2: Adding Type Persuasion for Primitive Types

Original from the old repo: https://github.com/Parquet/parquet-mr/pull/410
JIRA: https://issues.apache.org/jira/browse/PARQUET-2

These changes allow primitive types to be requested as different types than what is stored in the file format using a flag to turn off strict type checking (default is on). Types are cast to the requested type where possible and will suffer precision loss for casting where necessary (e.g. requesting a double as an int).

No performance penalty is imposed for using the type defined in the file type.  A flag exists to

A 6x6 test case is provided to test conversion between the primitive types.

Author: Daniel Weeks <dweeks@netflix.com>

Closes #3 from dcw-netflix/type-persuasion and squashes the following commits:

97f4e9a [Daniel Weeks] Added documentation as suggested by code review
1c3c0c7 [Daniel Weeks] Fixed test with strict checking off
f3cb495 [Daniel Weeks] Added type persuasion for primitive types with a flag to control strict type checking for conflicting schemas, which is strict by default.