CRAN release v0.13.1

git2r 0.13.1

BUG FIXES

• This is a bug-fix release to solve problems introduced in version
  0.12.1:
  • The bundled libgit2 source code has been reverted to commit
    (98f7bd2) from 2015-08-05 (same as in v0.11.0) to fix memory
    alignment errors (clang-UBSAN and gcc-UBSAN).
  • OpenSSL is now used again on OS X to provide the cryptographic
    support for HTTPS connections to fix a significant compiler
    warning (arithmetic on a pointer to void is a GNU extension
    [-Wpointer-arith]) on r-devel-osx-x86_64-clang.
  • Several fixes to the build configuration on non-Windows platforms.