String mememory is now managed in a much more sane manner.
Fixes include:
- git_person email and name is no longer limited to 64 characters
- git_tree_entry filename is no longer limited to 255 characters
- raw objects are properly opened & closed the minimum amount of
times required for parsing
- unit tests no longer leak
- removed 5 other misc memory leaks as reported by Valgrind
- tree writeback no longer segfaults on rare ocassions
The git_person struct is no longer public. It is now managed by the
library, and getter methods are in place to access its internal
attributes.