Switched to Maven Standard Directory Layout

Moved the source files around so that they match the Maven Standard Directory Layout. This should make it easier to create completely automatic builds for both the Windows and OS X versions. No code changes in this checkin, I just moved files and reconfigured the paths.

Note that I didn't move the src/recentchanges and src/version because the existing updater is checking those specific locations. The updater itself will need to be updated with new locations before those files are moved.

See also https://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html
Major overhaul of the screen detection to improve reliability

I've rewritten much of the screen detection code and recalculated the identifying pixels that should make screen detect more robust — and thus stop the recent problems some players have experienced with their games not being recorded due to missing deck or hero information, etc.

Some key changes:
- Screens are now identified by an enum `Screen`, and all the information needed to identify each screen is stored there so it's easy to find.
- All screens now check the same pixel locations, instead of each screen having its own set of unique pixels to check. This makes it easier to debug and reduces the risk that the HearthStats.net Uploader incorrectly matches multiple screens at once
- Simpler pixel check code makes the analysis much faster (though more work needs to be done to reduce the screenshot time, which is more significant)
- Added a JUnit test `ScreenAnalyserTest` which analyses a folder of screenshots and outputs an interpretation of each screen into a set of HTML files. This makes it much easier to debug screen detection errors because it allows you to run the analysis repeatedly until every screen is detected correctly.
- And, most importantly, I used that to test every screen and tweak all the numbers to make detection much more accurate :smile:

Some detection is still less than perfect, for example the victory & defect detection could use some work. I'll follow up with improvements to those hopefully in the new few days.

Also, so far this has only been tested on Mac OS X. Further tweaks may be needed for Windows before producing an official release of the HearthStats.net Uploader.