changed interfaces of read*.h to return bool,

added php-like pathinfo, dirname, basename functions,
pathinfo example

examples/pathinfo/example.cpp

@@ -0,0 +1,31 @@
+#define VERBOSE
+#include "pathinfo.h"
+using namespace igl;
+#include <string>
+#include <cstdio>
+#include <iostream>
+#include <fstream>
+using namespace std;
+
+int main(int argc, char * argv[])
+{
+  ifstream fin("input.txt");
+  if (fin.is_open() == false)
+  {
+    // error
+    return 1;
+  }
+
+  string line;
+  while( getline(fin, line) )
+  {
+    string dirname,basename,extension,filename;
+    pathinfo(line,dirname,basename,extension,filename);
+    printf("%s -> %s,%s,%s,%s\n",
+      line.c_str(),
+      dirname.c_str(),
+      basename.c_str(),
+      extension.c_str(),
+      filename.c_str());
+  }
+}