Core: Fix many "errors"/warnings and coding style (1)

Extractors, worldserver, authserver, shared and collision affected

Errors were found using Cppcheck, open-source static analysis tool

src/tools/map_extractor/dbcfile.cpp

@@ -3,12 +3,12 @@
 #include "dbcfile.h"
 #include "mpq_libmpq04.h"
 
-DBCFile::DBCFile(const std::string &filename):
-    filename(filename),
-    data(0)
+DBCFile::DBCFile(const std::string& filename):
+    filename(filename), recordSize(0), recordCount(0), fieldCount(0), stringSize(0), data(NULL), stringTable(NULL)
 {
 
 }
+
 bool DBCFile::open()
 {
     MPQFile f(filename.c_str());