Update task_list.py

-Limit max length of the string content for Task to 75 chars to avoid horizontal scroll overflow
-PEP8 Fixes
-Alternating Rows
-Remove SIGNAL import because not needed anymore
Merge pull request #18 from juancarlospaco/patch-1

[task_list.py] PEP8+Limit length of content(too much horizontal scroll)
Merge branch 'master' of https://github.com/ninja-ide/ninja-ide-plugins

Conflicts:
	plugins/src/taskPlugin/task_list/task_list.py