branch: handle NULL pointers passed to git_branch_iterator_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
config: handle NULL pointers passed to git_config_iterator_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
odb: handle NULL pointers passed to git_odb_stream_free

Signed-off-by: Brodie Rao <brodie@sf.io>
oid: handle NULL pointers passed to git_oid_shorten_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
refs: handle NULL pointers passed to git_reference_iterator_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
util: handle NULL pointers passed to git_strarray_free()

Signed-off-by: Brodie Rao <brodie@sf.io>
Show informational messages during cmake run as informational
Merge pull request #2039 from brodie/brodie/handle-null-on-free

Fix places in public free() functions where NULL pointers aren't handled
Merge pull request #2040 from scunz/cmake_msgs

Show informational messages during cmake run as informational
Fix a memory leak in `git_pathspec__vinit`.
Fix a memory leak in `git_config_iterator_glob_new`.
Fix a memory leak in `config_parse`.
Fix a memory leak in `hash_and_save` and `inject_object`.
Fix a double free issue in `git_blame__alloc`.

`git_blame_free` already calls `git__free` on `gbr`.
Add coverity-scan script
Incorporate @ethomson's suggestions.
Tweak travis secure config
Add coverity scan badge to readme
Refactor zlib for easier deflate streaming
Packbuilder stream deflate instead of one-shot