http_server followed by a trailing slash

File usage advice to use --http_server http://localhost/opencart (without trailing slash) and the CLI installer concatenate other directories without adding "/" before the concatenated directory thus saving wrong URLs in config files as eg.: http://localhost/opencartadmin
Added default value for config_image_location

There was no default value for config_image_location.
image_location_width and image_location_height are required fields in
store settings (store_form.tpl)
Fixed incorrect default path to logo.png and cart.png
Revert "Added default value for config_image_location"

This reverts commit 6b2bf6d2155ad199600b94c6db7870cc95a26688.
Added default value for config_image_location
duplicated code
Deleted white spaces
Added more event triggers.
Removed event sql from index.php
Added product_id to delete product event (it is not passed from controller in a way it can be identified)
Separated out the Event from controller while maintaining usability.

Events now live in a separate structure and cannot be directly accessed.
Fixed link url.

Closes #1578
Merge pull request #1617 from Urs-Bruelhart/patch-6

Deleted white spaces
Merge pull request #1608 from Dvir-Julius/patch-2

duplicated code same on line 573
Merge pull request #1606 from tjomamokrenko/master

Some fixes in default config values
Merge pull request #1301 from NanoCaiordo/patch-1

http_server followed by a trailing slash
Changed the response library/response.php to handle content type headers separately and default back to the text/html if not set. This will allow for correct control of json and xml response data.

New API code in catalog not yet updated as it is WIP by Daniel.

Closes #1633
Merge branch 'master' of https://github.com/opencart/opencart
Merge branch 'master' into Events-feature
Added new login/out events