Great optimization in ForkParser

There is a huge overhead in ForkParser ContentHandlerProxy and ContentHandlerResource read/write char[]/string methods. A simple change to not loop reading/writing each char of strings can result in speed ups of several orders of magnitude.

Tests with ~10k small RFC822 files (22MB), 24 parsing threads, have shown parse times below:

ForkParser off: 4s

ForkParser on: 30min

ForkParser patched: 17s

Also, there is a bug when running at least with Oracle JDK8 that, if a String greater than 65535 chars is written, a UTFDataFormatException is thrown from DataOutputStream.writeUTF(String) method.