Use std::max from algorithm to fix build failure with GCC 6.2.

[sebastic]

Lucas Nussbaum reported that sosi2osm failed to build in Debian Bug #835717:

g++ -g -O2 -fdebug-prefix-map=/<<PKGBUILDDIR>>=. -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 `pkg-config --cflags lua5.1-c++ fyba` -DLINUX -DUNIX -g  -c -o node.o node.cpp
node.cpp: In function 'long int createNode(double, double, short int)':
node.cpp:54:31: error: 'max' was not declared in this scope
      sizeM = max(1024, sizeM*2);
                               ^
<builtin>: recipe for target 'node.o' failed
make[1]: *** [node.o] Error 1

This appears to have been triggered by the update to GCC 6.2, and using std::max() from algorithm resolves the issue.

This change has already been included as patch in the Debian package to fix the release critical bugreport.