Some small compile errors

[barendgehrels]

Compiling GEOS with VC++2008 and stlport results in the following errors, which make sense and easy to solve.

1) WKBReader.h needs #include <string>

2) BufferBuilder.cpp, line 363 needs "std::sort" instead of "sort"

3) ConvexHull.cpp, line 272 needs "std::sort" instead of "sort"

4) ConvexHull.cpp, line 167 needs "std::unique" instead of "unique"

I use GEOS Version 3.0.3 on Visual C++ 2008 Express Edition with STLPort 5.2.1

[pramsey]

These appear to have been applied in trunk. Applied to 3.0 branch at r2242.

[(none)]

Milestone 3.1.0 deleted