fixed ArrayOutOfBoundsException in java example

[PHP] Fix typo

Related to https://github.com/google/flatbuffers/pull/3904#issuecomment-224724181

Fix typo

Create a maven like project structure for java development + OSGi + generation for test

clang formating header and code generators for cpp, general, js, php

Fix link to CONTRIBUTING

This allow jar generated with maven to be used in OSGi environment.

Verifier computes the buffersize, useful when streaming multiple flatbuffers

Fixed bug with negative hex constants (2).

Close #3898

Don't crash if str is null

Is useful especially when we want to create a string from another message string that might be null.

Rename CONTRIBUTING to CONTRIBUTING.md

Fixed operator++. Added CreateXXX for vector types.

Added --escape-proto-identifiers command-line option.

Fix for issue #3922

Also, clean up redundant ';' at end of java classes.