Fix various warnings.

The core, the scripts and the tools now compile without warnings with -Wall -Wextra -pedantic.

-Fix warnings from -Woverflow on implicit constant conversion.
-Fix a lot of warnings from -pedantic. Most of them are from the scripts and come from an useless semicolon in uses of PrepareAuraScript and PrepareSpellScript macros, which is also present in the examples. I corrected the example script in the scripts directory, but the one from http://collab.kpsn.org/display/tc/How+to%3A+Spell+system also needs to be corrected.
-Fix warnings from -Wformat.

Two minor changes in addition :

-Replace MAX_MONEY_AMOUNT, a defined value equal to 2^31 - 2 by std::numeric_limits\<int\>::max(). According to http://www.wowwiki.com/Money, the maximum money amount on WotLK is 2^31 - 1.
-Remove useless null-check on pointer returned by new. New doesn't returns nullptr on failure, it throws std::bad_alloc.