Solution for E4: Timing.

git-svn-id: https://epos.lisha.ufsc.br/svn/branches/ine5424@3109 86035c5f-d46c-4136-a2d5-fe63f1d4a782
Added .gitignore and directory workaround to professor's solution to E4.
Merged our solution to E4 with professor's.
The Handler class hierarchy chosen was ours, but with professor's
 additional helper classes and Alarm::handler() rewrite.