Use static_cast instead of C-style casts for non-fundamental types

A C-style cast is equivalent to try casting in the following order:

1. const_cast(...)
2. static_cast(...)
3. const_cast(static_cast(...))
4. reinterpret_cast(...)
5. const_cast(reinterpret_cast(...))

By using static_cast<T>(...) explicitly we avoid the possibility
of an unintentional and dangerous reinterpret_cast. Furthermore
static_cast<T>(...) allows for easier grepping of casts.

src/netbase.cpp

@@ -528,7 +528,7 @@ bool HaveNameProxy() {
 bool IsProxy(const CNetAddr &addr) {
     LOCK(cs_proxyInfos);
     for (int i = 0; i < NET_MAX; i++) {
-        if (addr == (CNetAddr)proxyInfo[i].proxy)
+        if (addr == static_cast<CNetAddr>(proxyInfo[i].proxy))
             return true;
     }
     return false;