Ignore Maven build directory
Ignore Eclipse project files
Set compiler source and target to 1.7

Perhaps later I will lower the target.  Or perhaps not.  For now the
initial development is done under OpenJDK 7.
Set source encoding to US-ASCII

ASCII is a subset of UTF-8 and it is very well supported.  Perhaps I
could use UTF-8, but I don't want any non-ASCII characters to sneak in
unnoticed.
Add Constants class
Ignore Emacs backup files
Add basic README and LICENSE files