Improve Proposal

[XJTUmg]

• [x] write and commit sample sql code for demo slides to repo "ExampleCode".
• [x] find more applications of connected components algorithms.
• [ ] make gantt chart for timeline.
• [x] reconsider timeline, try to make it better.
• [x] complete references.
• [x] recheck code.
• [x] format text with a standard font size.
• [x] remove references, add footnotes.
• [x] remove 'link', add link to the text.

[cvvergara]

FYI I think the time line is ok.

[XJTUmg]

• [x] enhance timeline to reflect these needs.
• [x] fix a link error in 'Benefits to Community' ('Read more')

[XJTUmg]

• [x] fix grammer mistakes.

[XJTUmg]

• [x] add cost and reverse_cost parameters to those three proposed functions.
• [x] add new reference ( pgRouting sample data )
• [x] investigate pgr_labelGraph. If it can be replaced with one of those three proposed functions, write about it in proposal.
• [x] add a new line to 'Attention' which has descriptions of the proposed sql queries. (use dijkstra like inner queries ).
• [x] analyze pgRouting Sample Data.

[XJTUmg]

• [x] review and check any requirement from OSGeo or GSoC.

[XJTUmg]

• [x] Add img about pgRouting Sample Data analysis.