gsoc:central list of columns, added sync and remove column list on db_structure page

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

fixing indentation in mult_submits.inc.php

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

naming convention,typos, indentaion fix and removed unnecessory file db_sync_central_columns.php

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

check if central columns storage is configured, if not configured don't show the option to sync/remove

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

add/remove columns to central list of columns from tbl_structure page

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

added icon image for central columns add/delete

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

add/remove of columns option in tbl_structure page in columns rows depending upon if column is already present in central columns or not

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

fixed php notices, apporiprate message when a non existing column is removed and when a existing column is added to cenral list

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

documentation added for central_columns configuration

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

regenerated sprite

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

changed central_columns table structure + modified functions to add to central column as per new tbl def

updated delete and other function as per new db structure

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

remove notices

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

sprintf for variable message

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

fix unit test failure errors

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

fixed whitespace issues plus function definition

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

refactoring code plus fixing coding style issues

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