add addSchemeData and import/export methods
add import/export methods
replace add/remove buttons by a menu with add, remove, rename, import
and export actions
add import_export module
Merge remote-tracking branch 'upstream/master' into import-export-theme
remove a "print"
Merge remote-tracking branch 'origin/master' into import-export-theme
Merge pull request #221 from elmamyra/import-export-theme

add import-export module for keyboard shortcuts and fonts & colors
chlog/pot/po/nl
make app.is_git_controlled() cheaper

dont try every time if the .git directory exists, instead remember the
result of the first call and return that next time.
Make app.is_git_controlled() cheaper
Add git module and test file

git module contains:

Git(object) class implementing functionality to manage
a git repository.
Currently this is only the repo Frescobaldi lives in, but later
we will also use this for managing project repos.

GitApp(Git) class used for the
app.repo
object representing Frescobaldi's repo.
Implements app.repo.upstream_remote()
Show Git branch/remote in Window title bar
Add initial Git.checkout()

For now it simply issues 'git checkout BRANCH'
Fix Git._run_git_command argument handling

When a single string is given as an argument (instead of a list)
we have to check for str _and_ unicode,
otherwise the string is exploded to a list.
Add app.repo.active_branch()

current_branch() may change during Frescobaldi's lifetime
while the application is run from the branch that was
current on startup.
Fix Git.checkout()

add the -q option because checkout returns its result
message to stderr
Add Git.tracked_remote_label()

return either 'local', the name of the remote
or remote/branch if the tracked branch has a different name.
Add Git menu

For now simply list all local branches.
Clicking on a branch tries to checkout this and restart the application.
If git gives an error (e.g. non-clean working tree) it aborts with a message box.
If checkout succeeds the user gets a message box and can restart
Frescobaldi now or later.