feat(gentool): generate only model

sytle(generate): remove verbose log

feat(field): add ALL

fix: GroutConcat should be GroupConcat

Merge pull request go-gorm#314 from go-gorm/fix_import_path

fix: model pkg path

feat(generate): default import model (go-gorm#311)

* feat(generate): render concurrently

* perf(generate): set GOMAXPROCS

* feat(generate): improve generate speed

feat(generate): render concurrently (go-gorm#308)

* feat(generate): render concurrently

* perf(generate): set GOMAXPROCS

docs(README): add GetFieldByName

feat(generate): parse table name with table prefix