cleanup
fix build: add includes
fix build: follow rename of "git_oid_mk*" to "git_oid_from*" in libgit2

See the following commit in libgit2:
commit fa48608ec30758dbf6d0d26d3c4f8efba8efe8e9
Author: Vicent Marti <tanoku@gmail.com>
Date:   Thu Jun 16 02:36:21 2011 +0200

    oid: Rename methods

    Yeah. Finally. Fuck the old names, this ain't POSIX
    and they don't make any sense at all.
fix build: follow rename of "*_free" to "*_close" in libgit2

See the following commit in libgit2:
commit 45e79e37012ffec58c754000c23077ecac2da753
Author: Vicent Marti <tanoku@gmail.com>
Date:   Sat Nov 26 04:59:21 2011 +0100

    Rename all `_close` methods

    There's no difference between `_free` and `_close` semantics: keep
    everything with the same name to avoid confusions.
fix build: change GIT_SUCCESS to 0

GIT_SUCCESS is obsolete in libgit2.
fix build: follow rename of "git_tree_entry_attributes" to "git_tree_entry_filemode" in libgit2

See the following commit in libgit2:
commit 9d7ac675d06dab2e000ad32f9248631af0191f85
Author: nulltoken <emeric.fermas@gmail.com>
Date:   Tue Aug 21 11:45:16 2012 +0200

    tree entry: rename git_tree_entry_attributes() into git_tree_entry_filemode()
fix build: follow rename of git_reference_oid to git_reference_target in libgit2

See the following commit in libgit2:
commit 2508cc66eb91597b12dc19721d9cea1f06e72107
Author: Ben Straub <bs@github.com>
Date:   Sun Nov 18 21:38:08 2012 -0700

    Rename ref and reflog apis for consistency
gettextpo-helper: link to libgit2 cleanly

"cmake/modules/FindLibgit2.cmake" obtained from the
https://github.com/libgit2/libgit2-backends repository from "CMake/".

Another Libgit2 CMake module is available at
https://github.com/julp/FindGIT2.cmake . It has more features (like
versioning), but it is not official.
add "make uninstall" target

http://www.cmake.org/Wiki/CMake_FAQ#Can_I_do_.22make_uninstall.22_with_CMake.3F
is_virgin_pot_content: check for "POT-Creation-Date:" field in header
add-templates-from-repo.rb: do not break on invalid POT files
is_virgin_pot_content: check presence of POT header
Store large amounts if hashes in a Set instread of Array
Rewrite "update" script in Ruby, add error handling
comment