* Use this chance to add a confirmation dialog when leaving the editors, to ask the user if he wants to save modifications. Fixes issue #1524.
* Also, enhance Mainform.RefreshTreeDB in a way that it does not trigger the OnFocusChange event. Important for the editors when saving changes.
* Keep only one TRegistry object in memory instead of creating a new one in each routine.
* Move out relevant functions and TRegistry object from main to helpers to make them usable globally.
a) some hundred lines of code from childwin.pas to main.pas
b) redundant hints/captions/shortcuts/events for similar buttons/menuitems to their corresponding TAction in main.dfm .
This change
a) avoids several inconsistent captions like described in issue #595
b) makes it easier to have toolbars on the mainform which are controlled by childform.
- Fixes bug #271 "F5 shortcut in database tree not working"
- Fullfills rfe #519 "Highlight selected item in tree view when focus is elsewhere"
- Fixes inconsistent expansion state of nodes after refreshing
- Fixes plus sign staying when a db node with 0 tables was selected
- Slightly enhances painting speed within the dbtree
- Removes temporary storage of a rightclicked node (DBRightClickSelectItem). VirtualTree handles its right clicked selection exactly like the left clicked one, which makes makes coding a bit cleaner as we can always use the selected item instead of hacking with the right and left clicked node. On the other side it removes a quite user friendly feature. Well, we can reimplement this feature later, though it's not user UNfriendly currently.
- Reasonably rename the StringList "OnlyDBs" to "DatabasesWanted" and "OnlyDBs2" to "Databases"
