Fix compilation with Android NDK

It seems ADL lookup is broken with the STLPort library. Peter says:

The compiler is gcc 4.4.3, but I don't know how many patches they
have applied to it. I think gcc has had support for Koenig lookup
a long time. I think the problem is the type of the vector iterator.
For example, line 272 in search.cpp:

 if (bookMove && count(RootMoves.begin(), RootMoves.end(), bookMove))

gives the error:

jni/stockfish/search.cpp:272: error: 'count' was not declared in this scope

Here RootMoves is:

 std::vector<RootMove> RootMoves;

If std::vector<T>::iterator is implemented as T*, then Koenig lookup
would fail because RootMove* is not in namespace std.

I compile with the stlport implementation of STL, which in its vector
class has:

 typedef value_type* iterator;

I'm not sure if this is allowed by the C++ standard. I did not find
anything that says the iterator type must belong to namespace std.
The consensus in this thread

http://compgroups.net/comp.lang.c++.moderated/argument-dependent-lookup/433395

is that the stlport iterator type is allowed.

Report and patch by Peter Osterlund.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>