HostOsInfo: Add some more useful abstractions.

Namely:
- path list separator
- executable suffix
- file name case sensitivity

All of these are duplicated in various places in the current Creator
code.

Change-Id: I86eb4662fa3c2071759bd728cae1aaf7111ae686
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>

src/plugins/git/gitsettings.cpp

@@ -84,7 +84,7 @@ QString GitSettings::gitBinaryPath(bool *ok, QString *errorMessage) const
         QString systemPath = QString::fromLocal8Bit(qgetenv("PATH"));
         if (!systemPath.isEmpty()) {
             if (!currentPath.isEmpty())
-                currentPath.append(Utils::SynchronousProcess::pathSeparator());
+                currentPath.append(Utils::HostOsInfo::pathListSeparator());
             currentPath.append(systemPath);
         }
         // Search in path?