The real position of a string is calculated by using the indirect() method,
which should be based on parentWidth and not byteWidth, as it was implemented.
We are also fixing the flag BUILDER_FLAG_SHARE_STRINGS on FlexBuffersBuilder
that was set as '1', same value as BUILDER_FLAG_SHARE_KEYS.
* [FlexBuffers][Java] Implementation of FlexBuffers API
This is the initial attemp to implement FlexBuffer on Java.
There is some limitations as compared to the C++ implementation:
1 - No mutations implemented yet
2 - Does not parse from json
Also, this initial implementation is not focused and performance, but
get the basics write. So there is many opportunities for optimization, for instance,
remove all enums, return CharSequence instead of Strings and object pooling.
* [FlexBuffers][Java] Optimizations and simplification of the Builder API.
This change removes BitWidth enum in favor of static ints. Also
make all "reads" APIs closer to C++ implementation (try to cast or convert
as much as possible, assuming user knows what he is doing). Finally,
we remove the helper classes for building vectors and maps.
There is no official benchmarks, but the unit tests are running in less
than 50% for previous runs, which mean those optimizations are worth it.
* [FlexBuffers][Java] Fix Reference::asString behavior
There was a incorrect assumption that strings would be null-terminated, which
could lead to truncated strings. S now it relies size instead of null-termination.
Other minor improvements
