Add initial SPIFFS library (#627)

* Add initial SPIFFS library

* Fix Deep Sleep Examples

* Missed one example

libraries/SPIFFS/examples/SPIFFS_Test/SPIFFS_Test.ino

@@ -0,0 +1,159 @@
+#include "FS.h"
+#include "SPIFFS.h"
+
+void listDir(fs::FS &fs, const char * dirname, uint8_t levels){
+    Serial.printf("Listing directory: %s\n", dirname);
+
+    File root = fs.open(dirname);
+    if(!root){
+        Serial.println("Failed to open directory");
+        return;
+    }
+    if(!root.isDirectory()){
+        Serial.println("Not a directory");
+        return;
+    }
+
+    File file = root.openNextFile();
+    while(file){
+        if(file.isDirectory()){
+            Serial.print("  DIR : ");
+            Serial.println(file.name());
+            if(levels){
+                listDir(fs, file.name(), levels -1);
+            }
+        } else {
+            Serial.print("  FILE: ");
+            Serial.print(file.name());
+            Serial.print("  SIZE: ");
+            Serial.println(file.size());
+        }
+        file = root.openNextFile();
+    }
+}
+
+void readFile(fs::FS &fs, const char * path){
+    Serial.printf("Reading file: %s\n", path);
+
+    File file = fs.open(path);
+    if(!file){
+        Serial.println("Failed to open file for reading");
+        return;
+    }
+
+    Serial.print("Read from file: ");
+    while(file.available()){
+        Serial.write(file.read());
+    }
+}
+
+void writeFile(fs::FS &fs, const char * path, const char * message){
+    Serial.printf("Writing file: %s\n", path);
+
+    File file = fs.open(path, FILE_WRITE);
+    if(!file){
+        Serial.println("Failed to open file for writing");
+        return;
+    }
+    if(file.print(message)){
+        Serial.println("File written");
+    } else {
+        Serial.println("Write failed");
+    }
+}
+
+void appendFile(fs::FS &fs, const char * path, const char * message){
+    Serial.printf("Appending to file: %s\n", path);
+
+    File file = fs.open(path, FILE_APPEND);
+    if(!file){
+        Serial.println("Failed to open file for appending");
+        return;
+    }
+    if(file.print(message)){
+        Serial.println("Message appended");
+    } else {
+        Serial.println("Append failed");
+    }
+}
+
+void renameFile(fs::FS &fs, const char * path1, const char * path2){
+    Serial.printf("Renaming file %s to %s\n", path1, path2);
+    if (fs.rename(path1, path2)) {
+        Serial.println("File renamed");
+    } else {
+        Serial.println("Rename failed");
+    }
+}
+
+void deleteFile(fs::FS &fs, const char * path){
+    Serial.printf("Deleting file: %s\n", path);
+    if(fs.remove(path)){
+        Serial.println("File deleted");
+    } else {
+        Serial.println("Delete failed");
+    }
+}
+
+void testFileIO(fs::FS &fs, const char * path){
+    File file = fs.open(path);
+    static uint8_t buf[512];
+    size_t len = 0;
+    uint32_t start = millis();
+    uint32_t end = start;
+    if(file){
+        len = file.size();
+        size_t flen = len;
+        start = millis();
+        while(len){
+            size_t toRead = len;
+            if(toRead > 512){
+                toRead = 512;
+            }
+            file.read(buf, toRead);
+            len -= toRead;
+        }
+        end = millis() - start;
+        Serial.printf("%u bytes read for %u ms\n", flen, end);
+        file.close();
+    } else {
+        Serial.println("Failed to open file for reading");
+    }
+
+
+    file = fs.open(path, FILE_WRITE);
+    if(!file){
+        Serial.println("Failed to open file for writing");
+        return;
+    }
+
+    size_t i;
+    start = millis();
+    for(i=0; i<2048; i++){
+        file.write(buf, 512);
+    }
+    end = millis() - start;
+    Serial.printf("%u bytes written for %u ms\n", 2048 * 512, end);
+    file.close();
+}
+
+void setup(){
+    Serial.begin(115200);
+    if(!SPIFFS.begin()){
+        Serial.println("SPIFFS Mount Failed");
+        return;
+    }
+    
+    listDir(SPIFFS, "/", 0);
+    writeFile(SPIFFS, "/hello.txt", "Hello ");
+    appendFile(SPIFFS, "/hello.txt", "World!\n");
+    readFile(SPIFFS, "/hello.txt");
+    deleteFile(SPIFFS, "/foo.txt");
+    renameFile(SPIFFS, "/hello.txt", "/foo.txt");
+    readFile(SPIFFS, "/foo.txt");
+    testFileIO(SPIFFS, "/test.txt");
+}
+
+void loop(){
+
+}