[BUGFIX] Local git repositories get no results
[CLEANUP] Removed unnecessary imports

In the source code there are many unused imports.
This commit removes them for a cleaner code base.
Resolve extension dependencies recursivly
Added Metrics extension as dependency
[FEATURE] Add option to list all available extensions
Fixed "KeyError: '__init__'" in extension list command
Merge pull request #27 from andygrunwald/help-list-extensions

[FEATURE] Add option to list all available extensions
Added recurslivly execution of dependencies
Added MessageWords as a dependency for MessageWordsPrint
Fix typo in word parameter
Fix typo in week extension
Fix parameter typo in Months extension
Merge pull request #36 from andygrunwald/resolve-extension-dependencies

Resolve extension dependencies recursivly
Merge pull request #37 from andygrunwald/metrics-evo-dependency

Added Metrics extension as dependency in MetricsEvo extension
Merge pull request #43 from andygrunwald/message-words-print-dependency

Added MessageWords as a dependency for MessageWordsPrint
Fixed typo in quiet / quit option in sample config file
Fix conflicts merging branch andygrunwald:local_branches_no_results

Conflicts:
	pycvsanaly2/GitParser.py
Merge pull request #26 from andygrunwald/unnecessary-imports

[CLEANUP] Removed unnecessary imports
[db] Add author's commit date

Some SCMs, like Git, make a distinction between the dates when
the committer and author pushed the changes.
The new field 'author_commit' was added to 'scmlog' table for storing
these data. The field will be set to NULL for those systems that
do not provide the dates.
Pysqlite2.apidb2 replaced by sqlite3