Fix warnings
Merge pull request #1957 from linquize/warning3

Fix warnings
Add some failing blame test cases
Duplicate all fields of a blame hunk
Fix buffer blame with new lines at end of file
Don't leak memory when duplicating a NULL signature
Minor cleanup
Merge pull request #1958 from libgit2/blame-fixes

Blame fixes
tests: make a few globals statics

ld was warning that the size of path changed, rightly so.