improvements to s7util

prevent writing data to read only part of spec
add row_offset, to add more write protection
add key checking, ignoring empty rows
prevent writing data to read only part of spec
better check parameters when setting data
implement client/server get/set so we can set TCP port
Merge pull request #16 from gijzelaerr/cli_getset

implement client/server get/set so we can set TCP port
add get/set for partner also
new release!
fix byte ordering in get/set_dword
Merge pull request #21 from schlamar/byte-order

fix byte ordering in get/set_dword
make Snap7 work on Windows again
Add Python3 support
remove depricated tests
add tox testing
prepare for release
add restype again
enable tests that work now
cleanup
prepare for 0.3.1
disable problematic tests on linux
disable more problematic tests for linux
fixes #27
Merge branch 'master' of https://github.com/spreeker/python-snap7

Conflicts:
	snap7/util.py