src: Updating code style to conform (more or less) to ndn-cxx style

Also, adding .clang-format that describes the applied style. Note that
this style requires a slightly customized version of clang-format.
diff --git a/utils/mem-usage.hpp b/utils/mem-usage.hpp
index a18448a..e58b9ad 100644
--- a/utils/mem-usage.hpp
+++ b/utils/mem-usage.hpp
@@ -42,58 +42,53 @@
  * @ingroup ndn-helpers
  * @brief Utility class to evaluate current usage of RAM
  */
-class MemUsage
-{
+class MemUsage {
 public:
   /**
    * @brief Get memory utilization in bytes
    */
-  static inline
-  int64_t
-  Get ()
+  static inline int64_t
+  Get()
   {
 #if defined(__linux__)
-/*
-/proc/[pid]/statm
-              Provides information about memory usage, measured in pages.  The
-              columns are:
+    /*
+    /proc/[pid]/statm
+                  Provides information about memory usage, measured in pages.  The
+                  columns are:
 
-                  size       (1) total program size
-                             (same as VmSize in /proc/[pid]/status)
-                  resident   (2) resident set size
-                             (same as VmRSS in /proc/[pid]/status)
-                  share      (3) shared pages (i.e., backed by a file)
-                  text       (4) text (code)
-                  lib        (5) library (unused in Linux 2.6)
-                  data       (6) data + stack
-                  dt         (7) dirty pages (unused in Linux 2.6)
+                      size       (1) total program size
+                                 (same as VmSize in /proc/[pid]/status)
+                      resident   (2) resident set size
+                                 (same as VmRSS in /proc/[pid]/status)
+                      share      (3) shared pages (i.e., backed by a file)
+                      text       (4) text (code)
+                      lib        (5) library (unused in Linux 2.6)
+                      data       (6) data + stack
+                      dt         (7) dirty pages (unused in Linux 2.6)
 
-Reference: http://man7.org/linux/man-pages/man5/proc.5.html
-*/
-    std::ifstream is ("/proc/self/statm");
-    if (!is.bad () && !is.eof ())
-      {
-        unsigned long vm;
-	unsigned long rss;
-        is >> vm   // the first number: virtual memory
-           >> rss; // the second number: resident set size
-        
-        return rss * getpagesize ();
-      }
-    else
-      {
-        return -1;
-      }
+    Reference: http://man7.org/linux/man-pages/man5/proc.5.html
+    */
+    std::ifstream is("/proc/self/statm");
+    if (!is.bad() && !is.eof()) {
+      unsigned long vm;
+      unsigned long rss;
+      is >> vm  // the first number: virtual memory
+        >> rss; // the second number: resident set size
+
+      return rss * getpagesize();
+    }
+    else {
+      return -1;
+    }
 
 #elif defined(__APPLE__)
     struct task_basic_info t_info;
     mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
 
-    if (KERN_SUCCESS != task_info (mach_task_self (),
-                                   TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count))
-      {
-        return -1; // something is wrong
-      }
+    if (KERN_SUCCESS
+        != task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count)) {
+      return -1; // something is wrong
+    }
 
     return t_info.resident_size;
 #endif