Empty tile response for jpg and webp

Faster and ~70% smaller empty png tile

.travis.yml

@@ -0,0 +1,23 @@
+language: php
+php:
+  - 5.3
+  - 5.4
+  - 5.5
+  - 5.6
+  - hhvm
+script:
+  - php tileserver.php
+after_success:
+  - wget https://github.com/klokantech/tileserver-php/releases/download/v0.1/grandcanyon.mbtiles
+  - git config --global user.email "travis@localhost.localdomain"
+  - git config --global user.name "Travis CI"
+  - git add --all
+  - git commit -am "Travis change"
+deploy:
+  provider: openshift
+  user: osm2vectortiles@klokantech.com
+  password:
+    secure: hiWKBaqh/CMdnQ2qxsRSKYAnk4tP/q2J50TaO+2sH09x+0Q85ygfICCDrEx457xqmGW0e4zZPsL83mMPvGt5KJO6g9DIncj6BFhpZA0ysnRJ3X1fczTiVN5hQfqNpa+/YIrQ0whu1Ur/IfdYTtvArYhuAPeigCloumGk9gNgSIQ=
+  domain: tileserver
+  app: php
+  skip_cleanup: true

README.md

@@ -1,5 +1,8 @@
-TileServer PHP - OGC Web Map Tiling Server (WMTS)
-=================================================
+TileServer PHP: MapTiler and MBTiles maps via WMTS
+==================================================
+
+[![Build Status](https://travis-ci.org/klokantech/tileserver-php.svg)](https://travis-ci.org/klokantech/tileserver-php)
+[![Docker Hub](https://img.shields.io/badge/docker-hub-blue.svg)](https://hub.docker.com/r/klokantech/tileserver-php/)
 
 This server distributes maps to desktop, web, and mobile applications from
 a standard Apache+PHP web hosting.
@@ -38,9 +41,9 @@ Requirements:
 -------------
 
 - Apache webserver (with mod_rewrite / .htaccess supported)
-- PHP 5.2+
+- PHP 5.2+ with SQLite module (php5-sqlite)
 
-(or anther webserver implementing mod_rewrite rules and PHP)
+(or another webserver implementing mod_rewrite rules and PHP)
 
 Installation:
 -------------
@@ -111,15 +114,11 @@ Supported protocols:
   Exposed at http://[...]/layer/z/x/y.grid.json
   
 
-To use the OGC WMTS services point your client (desktop or web) to the URL
+To use the OGC WMTS standard point your client (desktop or web) to the URL
 of 'directory' where you installed tileserver.php project with suffix "wmts".
-
 For example: http://www.example.com/directory/wmts
- 
-You can also install the project into a root directory of a virtual server:
-Then the address is: http://www.example.com/wmts
 
-Similarly for another end points.
+If you have installed the project into a root directory of a domain, then the address is: http://www.example.com/wmts
 
 The supported WMTS requests includes:
 
@@ -133,7 +132,7 @@ GetTile RESTful/KVP:
    http://[...]/layer/[ANYTHING-OPTIONAL][z]/[x]/[y].[ext]
    http://[...]?service=wmts&request=getTile&layer=[layer]&tilematrix=[z]&tilerow=[y]&tilecol=[y]&format=[ext]
    
-Another example requests are mentioned in the .htaccess.
+Other example requests are mentioned in the .htaccess.
 
 Performance from the web clients
 --------------------------------
@@ -180,10 +179,10 @@ Password protection
 HTTP Simple Authentication can be easily added to the server.
 Edit the .htaccess and add these lines:
 
-AuthUserFile /full/path/to/.htpasswd
-AuthType Basic
-AuthName "Secure WMTS"
-Require valid-user
+    AuthUserFile /full/path/to/.htpasswd
+    AuthType Basic
+    AuthName "Secure WMTS"
+    Require valid-user
 
 Create a file called .htpasswd with user:password format.
 You can use a command-line utility:
@@ -240,7 +239,7 @@ Tested WMTS/TMS clients
 BSD License
 -----------
 
-Copyright (C) 2012 Klokan Technologies GmbH
+Copyright (C) 2015 Klokan Technologies GmbH (http://www.klokantech.com/)
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without