Start of economy system

REALLY BASIC start
Worked a little more on Econ

Made independent of econ plugin, but broken until CMDH can write files
Obsolete courtesy of Jessassin making it MySQL
Merge pull request #1 from Jessassin/master

Update
Merge pull request #2 from Jessassin/master

Update
Added mail system

Added mail system.
NOTE: REQUIRES A DATABASE TABLE CALLED `mail` WITH COLUMNS `from`, `to`,
`message` (ALL STRINGS), AND `cleared` WHICH CAN BE EITHER AN ENUM SET
TO 'TRUE' AND 'FALSE' OR A STRING. ALSO NOTE: I WASN'T ABLE TO GET A
CHANCE TO TEST THIS, BUT IT SHOULD IN THEORY WORK.
Requested changes

- Removed unneeded @query-ies and return()s
- Added singular/plural
- Added invalid action if statement to /mail
Added [$=''] trick

Added the [$=''] trick. Explaination:
'/ra = foo' will only catch '/ra' and not '/ra invalid param'
'/ra [$=''] = bar' will catch anything that uses '/ra' as the base
command. It will just ignore any extra parameters the player gives. You
could make it drop an error if length($) > 0, but meh.
Merge pull request #3 from scienceguru1/master

Mail system added by ScienceGuru1 (CTMiner)
He also fixed some commands showing as unknown command if incorrect number of arguments passed