Bundle of enhancements and fixes

[lowell80]

Vladimir,

I'm finally getting around to a PR! Here's a collection of enhancements that I've been working with locally that would be nice to see in the upstream version, if you like them. I just pulled in your most recent enhancements into my forked version and would rather share this out then have to merge again. :-)

Changes:

• Adds a two new optional panels showing data feed (index/sourcetype) and data selection (eventtype) information, when available. (Closes #5, I suspect).
• Fixes "datamodel" mode search-type drop-down (Closes #11)
• Enhanced regex field validations from araman-m.
• Adds a note in the readme that will hopefully clear up that this addon can be used for non-CIM DM validation. (Closes #15)

Other minor changes:

• Shows the user the base-search selection (because if you're like me, I sometimes forget which tags go with which datamodel.)
• I started on a tstats-based data validation model (in a separate view). This isn't complete, but may be good enough to inspire some additional work. I didn't add it to the nav as it wasn't fully cooked.
• Expanded the "Events" panel to allow either table or event mode. You can get either all the results, or a representational sample (uses the "cluster" command). And the fields shown in the table can be limited to just the "recommended" ones, based on your new lookup.

Okay, last note! I also ran a code formatter which makes bloats the diff a bit. It's all in one commit (5a43bc5) so it can easily be reversed if you'd rather not, or want to see a smaller diff.