Change paths to logback config files. [1628]

I'm not wild about the new location of the XML files, but it's a start.
You'll probably want to run "ant clean" prior to building.

As of this commit, McV will look for a config file in two places, in
the following order:

1. build.xml's "logback.default.config" variable. Currently defaults to
"/Users/${user.name}/Documents/McIDAS-V". I'll try to work out
something better for Windows and Linux folks. This is the file that
you'd customize to suit your needs.

2. mcidasv.jar/logback.xml. This is the file that specifies the default
logging behavior.
Update logback paths in runMcV scripts. [1628]
Change log rolling policy. [1628]

Log files are now rolled upon starting McV, and the old log files will
reside in the "logs" subdirectory of the McV userpath.

This commit also means that McV is now compliant with the United States
Log Rolling Association's policies:
http://www.uslogrolling.com/html/rulesrankings.html
Fix invalid characters in XML. [1628]
Redirect java.util.logging to SLF4J. [1628]

This has the potential to be VERY noisy (but there was a lot of fun
internal stuff exposed by it). Let me know if there's anything I should
disable.
Merge pull request #80 from jon4than/logging_tweaks

Logging tweaks [1628]