Normalized database layout

Don't alter the database for every new upgrade, but just have a table to
keep the upgrade shortnames in. This also allows for more information
stored next to the upgrade level for each player. e.g. if the player has
the upgrade disabled or similar.
Load individual costmetic settings per client
Added internal handling of selected upgrade levels

Players can select which level of their purchased upgrade levels they
want to use.
Update smrpg_db_* admincommands for new db layout
Add SMRPG_SetClientSelectedUpgradeLevel native

Allows other plugins to change the selected level of a player's upgrade.
Added option to rpgmenu to change selected level

Players can toggle upgrade effects, change the active level to something
below their current purchased level and toggle cosmetic effects of the
upgrades individually!
Show selected upgrade level in upgrade settings menu
Added smrpg_disable_level_selection convar

Allow server admins to stop players from being able to change the
selected upgrade level.
Update the lastreset field in database on reset

Keep the database in sync when a player's stats get reset. Also display
the last time the player reset his stats in the admin menu.
Add SMRPG_ResetClientStats native
Merge branch 'database_rewrite'

Conflicts:
	scripting/smrpg/smrpg_admincommands.sp
	scripting/smrpg/smrpg_adminmenu.sp
	scripting/smrpg/smrpg_database.sp
	scripting/smrpg/smrpg_players.sp

Start using the new database layout and merge the 'showmenu' field in the players table in.
Instead of altering the upgrades table everytime a new upgrade is loaded and add a new field for it, normalize the table. This allows to save more info per upgrade than just the current level of the player.

Now players can select if they want to see or hear the visual effects of upgrades. They can also select which level of their already purchased ones of each upgrade they want to use. This allows them to "downgrade" their upgrades to handycap them against new players.