Implement resource parsing.

While here, fix a memory leak in pepy as I was not decrementing the
reference counter on self->data in section_dealloc().
Remove debugging.
Catch if PyInt_FromLong() returns NULL.
Fix a bug in test.py.

When iterating through the bytearray it would cause a python crash if
the byte value was 0x78. I have a test sample where the first 8 bytes
at the entry point are 0xe8 0xa6 0x4e 0x0 0x0 0xe9 0x78 0xfe. If I don't
do this dance it crashes when trying to get the 6th (0x78) byte out
of the array.
Fix resource parsing so it works. ;)

I had initially written this in such a way that it would break if there
were multiple entries anywhere other than the first table. This change
now works across more complex samples that I have tested against.

While here, I did a little moving around and had to create a structure
that isn't used other than to know how far to move the offset when
parsing. This is because the struct into which I am parsing the data
keeps track of other things along the way, so it's size is incorrect.

While here, change parse_resource() to be parse_resource_table() as it
is more accurate to what it really does.
Fix a type and expand a comment a bit.
Make resource parsing more resilient.

I have a UPX packed sample that corrupted the resource directory. These changes
allow the resources to be properly parsed.

They add an RVA and size to the resource struct. This is the address and size
of the resource as it is declared in the directory. If the address is invalid
create a zero-length buffer for the data. If the size is invalid (ie: it goes
off the end of the .rsrc section) create a zero-length buffer for the data.
Otherwise, return the actual data.

This allows consumers of the rsrc to figure out if the resource is corrupt
or not by comparing the length of the buffer to the size element. If the
size is greater than 0 but buffer is empty then it's invalid.

Also, it should never happen but just to be safe make pepy catch NULL
buffers (in pepy_data_converter) and return an empty bytearray.
Document size and RVA changes.
Merge pull request #6 from wxsBSD/resources

Implement resource parsing.