Reflect camelot in pypdf_table_extraction namespace

[foarsitter]

This is the elaboration of #9 and the first step in rebranding.

I copied the file structure to /pypdf_table_extraction and imported all the objects from camelot where needed. This way I tried to achieve to be completely backwards compatible.

from camelot.backends.poppler_backend import PopplerBackend
from pypdf_table_extraction.backends.poppler_backend import PopplerBackend

from camelot.handlers import Lattice,Stream
from pypdf_table_extraction.parsers import Lattice,Stream

[bosd]

LGTM,
Maybe put line end at test_rename.py 😉

[foarsitter]

@MartinThoma can I have your opinion here?

[chapmanjacobd]

probably better to do pdf_table_extraction or pypdf_table_extraction