First version of 'designing abstract data types' reading
Minor updates to lab on classes
Minor updates to Eclipse lab
Fix typo in Command-Line git lab
Minor updates to lab on reading Java
Reformat code in objects reading
Minor update to reading on ADTs
Minor code cleanup in intro java reading
Add 'Simple Java for C Programmers' to the first set of readings
Cleanup of "Simple Java for C Programmers"

* Fix some code.
* Eliminate the unused sections at the end.
* Other minor changes.
Reformat code in reading on standard methods
Add reading on data structures