Verify castability before actually doing it

We are experiencing problems with mis-formed lines, where we think a
field is supposed to be a Map, but due to a series of unfortunate events
it is actually a String. When we encounter this line, Hive flips out and
fails the entire job due to a recurring ClassCastException.

This patch simply checks the castability of the variable before actually
doing the cast. It returns NULL if it's not castable, and logs the
toString() of it at warn level.
Merge branch 'release/1.1.7' into develop
committing
Making SerDe smarter when handling numeric numbers. Keep string representation till it's actually time to parse it, this way the JSON parser does not need to know in advance if a number should be a short, into or large int.
Work towards solving #34 and #45
working on unit tests
Completed all the Primitive OI for all numeric types, with unit tests.
added a bunch of unit tests. Also, centralized primitive parsing in an utility class
Merge branch 'feature/better-number-handling' into develop

Fixes #39, #45, #34 #29, #26, #22, #13
moved to jgitflow for release
updated cloudera dependencies
updating poms for 1.1.8 release
changed readme
updating poms for 1.1.8 release
updating poms for 1.1.8 release
no deploy
updating poms for 1.1.8 release
updating poms for 1.1.8 release
updating poms for 1.1.8 release
updating poms for 1.1.8 release
Merge branch 'release/1.1.8' into develop