RFR: git: support unicode filenames [v3]

[Erik Helin]

> Hi all,
> 
> please review this patch that adds support for unicode filenames to `GitRepository`. I also added a unit test
> exercising the new functionality.
> Testing:
> - [x] `make test` passes on Linux x64
> - Added a new unit test
> 
> Thanks,
> Erik

Erik Helin has updated the pull request incrementally with one additional commit since the last revision:

  Do not run test with Mercurial

-------------

Changes:
  - all: https://git.openjdk.java.net/skara/pull/728/files
  - new: https://git.openjdk.java.net/skara/pull/728/files/3097f5b7..d4b9902a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=728&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=728&range=01-02

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/skara/pull/728.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/728/head:pull/728

PR: https://git.openjdk.java.net/skara/pull/728