Summary:
Merge branch 'master' of https://github.com/lubuntu-team/manual
1.3 Images added
deleted uneeded images
Fixed minor typos raise in tsimons concerns.
Minor changes, removed test Renamed discover to Discover software center.
removed test
Added a section for software management. Added tags to help search in documentation.
Test Plan: Sample test
Differential Revision: https://phab.lubuntu.me/D39
1. Corrected typos like "Useage" should be "usage". Many other minors.
2. Restructured paragraph, making it more readable
3. Adding an example to the Usage section.
4. Extended the overview to give a better description of the application. I took some information from the official site.