add a test case to ensure that a statement's id is not overwritten when it is stored in a learning record store (for #1)
rename RequestExecutor to Handler and move it to the Request subnamespace
Fixed issue #1. When predefined id is setted, It doesn't spect content from store request (following xAPI spec 204 is used when id is included), so in case of 204 we don't need to fill id
Change code style to original
Refactor for clean code
Merge branch 'hotfix_1'

# By jpcid (3) and Christian Flothmann (2)
* hotfix_1:
  Refactor for clean code
  Change code style to original
  Fixed issue #1. When predefined id is setted, It doesn't spect content from store request (following xAPI spec 204 is used when id is included), so in case of 204 we don't need to fill id
  rename RequestExecutor to Handler and move it to the Request subnamespace
  add a test case to ensure that a statement's id is not overwritten when it is stored in a learning record store (for #1)

Conflicts:
	Client/Api/StatementsApiClient.php