Tools/MMAPs: Fix uninitialized value in mmap_generator

Fix uninitialized value in mmap_generator. This fixes mmaps_generator broken in some build configurations.
Fixes #12644
Core/Misc: Remove unused variable
Core: Fix build for vs2014
Revert "Core: Fix build for vs2014"

This reverts commit e3034511890f4c918d758a6b6b239c14f10b75e2.
Core/NetworkIO: Handle exceptions thrown from socket constructor when retrieving remote address
Core/NetworkIO: Allow receiving packets bigger than buffer size