Add Copy method to NetworkBuffer

Copy values from the NetworkBuffer, taking into account network byte
order to host byte order.
Add methods to serialize and deserialize array of ints to NetworkBuffer
Add Copy tests for out-of-bounds and overflow
Merge pull request #24 from tcoyne/copy-from-buffer

Add Copy method to NetworkBuffer
Add ability for buffer to switch endian conversion

Turns out that netbios headers are big endian, but all SMB (all versions) are
little endian.
Make the endian switch barrier a template parameter

Since we have the size of the buffer as a template anyway
Make unit tests us the templated switch index rather than assuming 4

The unit tests assumed the original implementation of a hardcoded switch at
index 4 (for netbios sessions). Update the unit tests to use the templated
switch index and add a test for no switch (index 0).
Merge branch 'buffer' into smb

Conflicts:
	src/buffer.hpp
	src/parser.cpp
	src/serializable.hpp
	test/buffer_test.cpp