add user defined column to central list

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

using functions from tbl_columns_definition_form.lib.php to create the add column form

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

fix Coding styl

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

added unit test for new function PMA_getHTMLforAddNewColumn

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

bug fix: added function to get columns count in central list

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

using functions from tbl_columns_definition_form.lib.php to edit columns in central list

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

improved test

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

Bug/coding style fix

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

Fix delete issue

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>

added missing doc element

Signed-off-by: Smita Kumari <kumarismita62@gmail.com>
Merge pull request #1233 from smita786/gsoc_central_columns_list

add user defined column to central list