Fix Bad request exception (it expects boolean).

Use of implemented methods for manipulation with boolean values for
update user such as
* can_see_managed_users
* is_exempt_from_device_limits
* is_exempt_from_login_verification
* is_sync_enabled
fails because set functions such as:
* setCanSeeManagedUsers(boolean)
* setExemptFromDeviceLimits(boolean)
* setExemptFromLoginVerification(boolean)
* setSyncEnabled(boolean)
accepts correctly boolean values but internally changes the boolean
values true / false to string values “true” / “false” and update
procedure fails with Bad request exception (it expects boolean).
Merge pull request #182 from laszlohordos/master

Fix Bad request exception (it expects boolean).