test suite cleanups

Cleaned up the test suite and made it as presentable as possible.
Conformed style, formatting, and practices.

Assert's tests are lauded as examples and reference material - we
can't have them be difficult to read and understand or contain
anti-patterns.

@jcredding basically touched every file in the test suite so the diff is rugged.  Here is the summary of the changes:
* moved all files into "test/{unit|system|support}" subdirs
* ended each test file with "_tests.rb"
* in each test file
 * renamed all contexts to end in "Tests"
 * reformatted for 80 char width and pruned unnecessary code and empty lines and whitespace

In addition to this reformatting stuff, I had to tweak the assertions a bit.  I reordered the methods to be alphabetically ordered and redid the "check_exceptions" stuff.  I made it a utility class implementation that removed a lot of conditionals.  Those changes should be more obvious in that file's diff.

Look over and double check I didn't screw anything up - thanks man.