fixe vc++ link error

fix link error with vc++

you need instead binding.gyp at line 19 
to 
'libraries' : ['libpq.lib'],

```
**Linker Command Line**
/OUT:"E:\booo-node-postgres-eedc5a9\build\Debug\binding.node" /INCREMENTAL /NOLOGO /LIBPATH:"D:/PROGRA~1/POSTGR~1/8.4/lib\" /DLL "C:\Users\Vernice\.node-gyp\0.8.0\Debug\node.lib" "libpq.lib" "kernel32.lib" "user32.lib" "gdi32.lib" "winspool.lib" "comdlg32.lib" "advapi32.lib" "shell32.lib" "ole32.lib" "oleaut32.lib" "uuid.lib" "odbc32.lib" "odbccp32.lib" /MANIFEST /ManifestFile:"Debug\obj\binding\binding.dll.intermediate.manifest" /ALLOWISOLATION /MANIFESTUAC:"level='asInvoker' uiAccess='false'" /DEBUG /PDB:"E:\booo-node-postgres-eedc5a9\build\Debug\binding.pdb" /PGD:"E:\booo-node-postgres-eedc5a9\build\Debug\binding.pgd" /TLBID:1 /DYNAMICBASE /NXCOMPAT /MACHINE:X86 /ERRORREPORT:QUEUE 
```