Code handling

• sgs_ExecBuffer - execute a character buffer
• sgs_EvalBuffer - execute a character buffer, keep returned variables on stack
• sgs_ExecString - execute a null-terminated string
• sgs_EvalString - execute a null-terminated string, keep returned variables on stack
• sgs_ExecFile - execute a file
• sgs_EvalFile - execute a file, keep returned variables on stack
• sgs_Include - include an item from the file system
• sgs_IncludeExt - include an item from the file system, optionally specifying a search path
• sgs_Compile - compile character buffer to bytecode buffer
• sgs_DumpCompiled - dump bytecode/constant info from a compiled bytecode buffer
• sgs_GetScriptFSFunc - return the current virtual file system callback and its user data pointer
• sgs_SetScriptFSFunc - set the virtual file system callback and its user data pointer
• sgs_StdScriptFSFunc - default virtual file system function