Implemented fake command

Fake a migration in a chosen environment (set "up" status without executing).

For example, SQL code inside FirstMigration will not be executed after this commands:

```sh
$ bin/phinx status -e development
Phinx by Rob Morgan. version 0.3.6

using config file ./phinx.yml
using config parser yaml
using migration path /%path%/migrations
using environment development

 Status  Migration ID    Migration Name
-----------------------------------------
   down  20140703180511  FirstMigration
   down  20140703180516  SecondMigration

$ bin/phinx fake -e development -t 20140703180511
Phinx by Rob Morgan. version 0.3.6

using config file ./phinx.yml
using config parser yaml
using migration path /%path%/migrations
using environment development
using adapter mysql
using database phinx

All Done. Took 0.0133s

Status  Migration ID    Migration Name
-----------------------------------------
     up  20140703180511  FirstMigration
   down  20140703180516  SecondMigration
```