Update feature: Moved install requirements to System class

Moved install requirments to System::check with module support to allow
override the requirments for reusability as part fo #581
Fixed issue: Fixed some typos
Fixed issue #581: Ugly hack to fix both mysql and mysqli in Installer
Fixed issue: Fixed systeminfo widget and cleanup
Updated Issue #373: Removed system/request/client
Updated Issue #373: Removed system/request/exception
Updated Issue #373: Removed system/request/client/curl
Updated Issue #373: Removed system/request/client/external
Updated Issue #373: Removed system/request/client/internal
Updated Issue #373: Removed system/request/client/stream
Updated Issue #373: Removed system/request/client/http
New feature: Added Request_Client_Recursion_Exception as part of Request_Client Class
New feature: Added some vars
Merge pull request #584 from sergeyklay/master

Minor fixes
Merge pull request #585 from sergeyklay/feature-new-vars

Added some vars
Merge pull request #586 from sergeyklay/feature-request

New Request Client
Fixed issue: Broken request class on ko3.3 update. Still rough edges
Fixed issue #586: Revert to 57f48ba