report git commit description if testing from a repository
protect t/readpref.t from bad MONGOD environment variable
Revert "Fix MinGW compile with ActivePerl 64-bit 5.16"

This reverts commit 4d7321f7793507ad3ce650c1433b5f5bae379369.
Merge remote-tracking branch 'upstream/master'
Added build artifacts to .gitignore