Update 02.5.md

结尾处“共有”改为“公有”。
合并两次b.Volume()为一次调用

合并两次b.Volume()为一次调用，培养注重效率的习惯，充分利用Go的if可设初始值的特性。
A few typos & minor improvement: Sayhi => SayHi, etc.

小细节改进。谢谢老谢分享的大作，很适合学习Go。
“显示的”=>“显式的”; rob => Rob
微小改动
Merge pull request #269 from 6yf/patch-1

"2.5 面向对象"结尾处“共有”改为“公有”。
Merge pull request #270 from 6yf/patch-2

合并两次b.Volume()为一次调用
Merge pull request #271 from 6yf/patch-3

A few typos & minor improvement: Sayhi => SayHi, etc.
Merge pull request #272 from 6yf/patch-4

“显示的”=>“显式的”; rob => Rob
Merge pull request #273 from 6yf/patch-5

微小改动
Corrected format for `Description`

Corrected format for `Description`
Merge pull request #275 from LarryBattle/master

Corrected format for `Description`
Merge pull request #1 from astaxie/master

合并原作者的更新20131129