[log] Fix #48 incorrect source line w/ copy paste

- until there is a better way ....

Merge pull request #44 from dyweb/log/v2.3

[log] Support fields (structured logging) and source line

- json handler
- cli handler with delta time (like log v1 and logrus)
- color package

Merge pull request #42 from dyweb/log/v2.0.2

[generator] Support go template in gommon generate

- was planning to do logger, but started with the generator, and the work in #43 deserve a fresh new PR (since it may not be finished  ....)
- we can copy the TODO list to new PR though :)