upgrade to latest eclipse version: photon (#194)

* upgrade to latest eclipse version: photon

* Update tycho to 1.2.0

* add space back

Author: andxu

.travis.yml

@@ -1,10 +1,8 @@
 language: java
 
-matrix:
-  include:
-    - os: linux
-    - os: osx
-      osx_image: xcode9.2
+os:
+  - linux
+  - osx
 
 script: 
   - ./mvnw clean verify

pom.xml

@@ -11,7 +11,7 @@
     <properties>
         <base.name>Java Debug Server for Visual Studio Code</base.name>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <tycho-version>1.1.0</tycho-version>
+        <tycho-version>1.2.0</tycho-version>
     </properties>
 
     <licenses>
@@ -150,9 +150,9 @@
     </build>
     <repositories>
         <repository>
-            <id>oxygen</id>
+            <id>photon</id>
             <layout>p2</layout>
-            <url>http://download.eclipse.org/releases/oxygen</url>
+            <url>http://download.eclipse.org/releases/photon</url>
         </repository>
         <repository>
             <id>oss.sonatype.org</id>