Add bash script for updating copyright headers

This script is largely inspired from a Request from Curtis Rueden and should
be called with a positional argument equal to the current year, e.g.
$ bash tools/update_copyright 2015
Split pattern
Add logic to update single year copyrights
Attempt to fix sed issue
Add check for copyright year arguments
Fetch all tags befor mvn, cpp and cppwrap builds

Since Travis clones the repository with a default depth of 50, builds using a
tag can fail. This commit should fix failures by fetching all Git tags.
Add differential beahvior between FreeBSD and GNU versions of sed
Add logic to handle FreeBSD and GNU sed differently

Also allow the date to default to the current year
Fix single year copyright edition
Do not replace single year copyright with current year
Fix GNU version of the script
Merge pull request #1466 from sbesson/rebased/dev_5_0/copyright_tools

Add bash script for updating copyright headers (rebased onto dev_5_0)