Fix TypeError in pkg.group_install

Package groups are case-insensitive, so convert the group names to
lowercase in group_info to ensure that matches are found.

However, if the group does not exist, this same traceback will happen.
Resolve this by using dict.get.

This fixes #4260.
Merge pull request #4331 from ranl/develop

making deploy_war function work on windows
Add a needed extra space so it works on cli
Merge pull request #4332 from UtahDave/fix_docs

Add a needed extra space so it works on cli
Fix typo: s/mimion/minion/
Merge pull request #4333 from dlindquist/develop

Fix typo: s/mimion/minion/
Merge pull request #4330 from terminalmage/issue4260

Fix TypeError in pkg.group_install
use os.path.basename instead of split() for the deploy_war to be supported in windows