Add GitShellIntegration - shell based git support

This class simply uses the git command and no longer requires any git
python bindings to be around. It is very useful as everyone using git
has git installed but may not have python-git (or python3 support for
python-git) installed.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Fix PEP8 issues

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Bump copyright for 2012-2014

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Add __all__ to versiontools

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
fixup bzr sh support
Update changelog

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Handle OSError in shell integration

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Fix python-git code not to shadow a variable

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Fix various PEP8 issues

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Fix tests for python3.3

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Stop supporting << python2.6, python3.1, support up to 3.4

This patch marks python2.4, python2.5 and python3.1 as unsupported while
marking python3.2, python3.3 and python3.4 as supported.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
Add .travis.yml

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>