Add cf getters for properties

src/db.rs

@@ -1167,12 +1167,38 @@ impl DB {
         }
     }
 
+    pub fn property_value_cf(&self, column_family: ColumnFamily, name: &str) -> Option<String> {
+        let prop_name = CString::new(name).unwrap();
+        unsafe {
+            let value = ffi::rocksdb_property_value_cf(
+                self.inner,
+                column_family.inner,
+                prop_name.as_ptr()
+            );
+
+            if value.is_null() {
+                return None;
+            }
+
+            let s = CStr::from_ptr(value).to_str().unwrap().to_owned();
+            libc::free(value as *mut c_void);
+            Some(s)
+        }
+    }
+
     pub fn property_int_value(&self, name: &str) -> Option<u64> {
         match self.property_value(name) {
             Some(value) => value.parse::<u64>().ok(),
             None => None,
         }
     }
+
+    pub fn property_int_value_cf(&self, column_family: ColumnFamily, name: &str) -> Option<u64> {
+        match self.property_value_cf(column_family, name) {
+            Some(value) => value.parse::<u64>().ok(),
+            None => None,
+        }
+    }
 }
 
 impl WriteBatch {