This memset was being reached after the entire packfile under
WinHttp, so the byte count was being lost for small repos.

Cmake flags clean

Stash

- No overwriting allows control from cmake cache or cmdline
- -g is already the CMake default
- -O0 is already gcc's default

- Those are the RelWithDebInfo flags.
- They should be controlled from CMAKE_BUILD_TYPE

- For Debug builds, CMake uses concatenated
  CMAKE_C_FLAGS and CMAKE_C_FLAGS_DEBUG
- This reverts commit 291f7122.

remove /ZM1000 from msvc builds

Updates config upon moving and deletion of branches

Pedantic ordering of GIT_UNUSED vs. variable declarations.

Progress callbacks

reset changes for merge

git_indexer_stats and friends -> git_transfer_progress*

Also made git_transfer_progress members more sanely
named.