Add support for -h/--help options.

RHBZ#962168. In response to user request added support for invoking with the -h
or --help argument to print usage information. Previously usage was only
printed if the user provided less than two arguments AND did not provide any
invalid arguments, as they were unhandled the commonly used -h and --help
arguments counted as invalid.

https://bugzilla.redhat.com/show_bug.cgi?id=962168

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Refer to manual page in usage.
Bump copyright year.
Fix performance issue for huge repositories

Problem: gitstats will read every commit and every file in repository in one
thread during initial statistics generation (i.e. no cache available). It may
take much time in case of huge repositories (100 000+ files) Solution: Execute
all read commands in 24 threads instead of one

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Make number of processes configurable.

Default to 8.
Fix minor documentation issues

* author.txt was renamed to AUTHOR
* use git shortlog instead of git-shortlog
  because the latter is not necessarily in PATH

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Remove backticks from author names passed to gnuplot.

Without this, author names containing `touch /tmp/vulnerable` would cause said
file to appear after generating statistics for the given repository.

This is not an optimal solution. Instead of blacklisting characters we should
either whitelist some, or find a safe escape mechanism for gnuplot.
Bump README python requirement to 2.6.0.

The code already checks for python 2.6.
fix: let "Pool" for line count data collection honor "processes" configuration setting

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Y-Axis of graphs start at zero

Fix the base of graph y-axes at zero to prevent misleading graphics.

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Bump copyright year.
Go back to previous dir to no fail on relative paths

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Fix indentation to be consistent.
properly terminate created subprocesses

This fixes a memory / ressource leak that manifests when computing
stats over big sets of repositories. It was eating more than 8G of
memory for ~15 git repositories.

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
implement a way to limit the statistics to commits after a start date

This is really useful when computing statistics over a set of
repositories, where some repositories are much older than other.

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Document start_date option on the manpage.
How to merge author information.

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Removed useless merge_authors configuration option. Use .mailmap instead.

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Added HTML header meta tag so that author names will be shown correctly also when the file is opened in a browser.

Signed-off-by: Heikki Hokkanen <hoxu@users.sf.net>
Add missing xhtml end tag.