Fix WriteMultiVars padding when last item has odd bytes

[MohamedGobran]

Summary

Fixes WriteMultiVars function that incorrectly applied padding after the last data item when it had an odd number of bytes, causing write failures.

Changes

• Fixed padding condition in WriteMultiVars to only pad between items, not after the last item
• Added .gitignore file for common build artifacts

Problem

The original code:

if (ItemDataSize % 2 != 0)

Applied padding to ALL odd-sized items, including the last one, corrupting the packet.

Solution

if ((ItemDataSize % 2 != 0) && (c < ItemsCount - 1))

Only applies padding between items.

Protocol Reference

According to reverse-engineered S7 protocol documentation:

"The Data Item structures must begin on even bytes so if their length is an odd number and there is a following Data Item then they are padded with a zero byte."

Source: The Siemens S7 Communication - Part 2 Job Requests and Ack Data

The key requirement is padding only when there is a following Data Item - not after the last item.