Change env.Environment.BeforeTest to env.Environment.BeforeEachTest

[vladimirvivien]

Currently, the env.Environment method that registers pre-test callbacks is named BeforeTest. That name could be more descriptive to indicate the frequency at which that those operations, registered with the method, are executed during test execution.

By changing the name to BeforeEachTest test writers can clearly deduce when the test is executed during framework execution as shown in the following steps:

- env.Environment.Setup
- TestFunction
  - env.Environment.BeforeEachTest
  - env.Test(feature)
  - env.Environment.AfterEachTest
- env.Environment.Finish