lvarray: fix cppcheck warnings

```
warning: Rethrowing current exception with 'throw;', it seems there is no current
exception to rethrow. If there is no current exception this calls std::terminate().
```

crengine/include/lvarray.h

@@ -130,10 +130,7 @@ class LVArray
  /// copies range to beginning of array
  void trim( int pos, int count, int reserved )
  {
-#if defined(_DEBUG) && !defined(ANDROID)
- if ( pos<0 || count<=0 || pos+count > _count )
- throw;
-#endif
+ assert(pos >= 0 && count > 0 && pos+count <= _count);
  int i;
  int new_sz = count;
  if (new_sz < reserved)
@@ -154,10 +151,7 @@ class LVArray
  /// removes several items from vector
  void erase( int pos, int count )
  {
-#if defined(_DEBUG) && !defined(ANDROID)
- if ( pos<0 || count<=0 || pos+count > _count )
- throw;
-#endif
+ assert(pos >= 0 && count > 0 && pos+count <= _count);
  int i;
  for (i=pos+count; i<_count; i++)
  {