Folder/Package Renaming

[colin-axner]

Currently the bulk of the application is under the package types. The name "types" does not accurately represent all the files it contains. I think we should split this package into 2. 1 folder/package containing files for validation and low level database changes (mapper) and the other folder/package for higher level application changes and structure definitions.

For example we could have the packages auth and db:
package auth contains:

• mapper.go
• ante.go
• utxo.go

package db contains:

• handler.go
• tx.go
• keeper.go
• errors.go

To work with the current version of the cosmos sdk we should add a errors.go file to define the codespace our errors will function in as outlined here. Notice that none of the files in package auth need to return an sdk.Error.

Thoughts?

[hamdiallam]

I like the division

[colin-axner]

To avoid circular dependencies here is an outline of the updated package ordering:
There are five packages : app, auth, db, types, and utils

• app: app.go, app_test.go

• auth: mapper.go, mapper_test.go, ante.go, ante_test.go, handler_test.go (can't be put in db or it creates a circular dependency, needs to be able to construct a mapper)

• db:errors.go, handler.go, kepper.go, tx.go, tx_test.go

• utils: utils.go

• types:utxo.go, mapper.go (interface for utxo mapper)

[colin-axner]

Updated spec in #25