Updated JUnit dependency
Improved build configuration
Require Java SE 6 or greater
Expanded imports

Import order list:
java
javax
*
* (static)
Added a copyright statement
Basic error recovery. Fixes #11

Class BibTeXParser provides two parsing modes. Method #parse(Reader)
represents "normal" parsing mode, which throws an exception if an error
condition is detected. Method #parseFully(Reader) represents "error
recovery" mode, which skips an erroneous object definition and continues
with the next object definition until the end of the BibTeX document is
reached.