Improve graphic assets for documentation.

Author: garrettrayj

.editorconfig

@@ -0,0 +1,4 @@
+root = true
+
+[*.csv]
+insert_final_newline = false

README.md

@@ -1,7 +1,7 @@
 PHP7 Mapnik
 ===========
 
-<img src="docs/assets/header_graphic.png?raw=true" alt="PHP7 Mapnik" title="Generated by PHP7 Mapnik" width="640" height="160">
+<img src="docs/assets/readme_header_image.png?raw=true" alt="PHP7 Mapnik" title="Generated by PHP7 Mapnik" width="640" height="160">
 
 Introduction
 ------------

docs/assets/docs_index_background.png

@@ -1,6 +1,6 @@
 body {
     align-items: center;
-    background: url('docs_index_background.png') center center;
+    background: url('documentation_index.png') center center;
     background-size: cover;
     display: flex;
     font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
@@ -43,4 +43,4 @@ main > header > p {
 
 #main-nav > ul > li a:hover {
     background: white;
-}
+}

docs/assets/documentation_index.png

@@ -1,8 +1,8 @@
-<Map background-color="darkslateblue" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
+<Map background-color="slateblue" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
     <Style name="world_style">
         <Rule>
-            <PolygonSymbolizer fill="slateblue" />
-            <LineSymbolizer stroke="rgba(255,255,255,0.5)" stroke-width="0.2" />
+            <PolygonSymbolizer fill="darkslateblue" />
+            <LineSymbolizer stroke="mediumslateblue" stroke-width="0.5" />
         </Rule>
     </Style>
 
@@ -13,4 +13,4 @@
             <Parameter name="file">ne_110m_admin_0_countries.shp</Parameter>
         </Datasource>
     </Layer>
-</Map>
+</Map>