StatsX Language/Translation Update

Updates to StatsX for per-user translation support. Fixes [bug 3040](https://bugs.alliedmods.net/show_bug.cgi?id=3040)

* Removed occurances of LANG_SERVER where possible
* And a lot of smaller, general improvements:
 * removed all implicit usage of global buffers
 * formatex used instead of format
 * removed hardcoded string lengths and defines in favor of the charsmax macro
 * fixed a small code piece where player id caching was accidentally not used
 * switched replace_all to the new replace_string
 * moved cvar usage from named access to pcvars
 * moved spawn detection from resethud to Ham_Spawn
 * set_task now uses the smallest possible 0.1 as the timer