Fixed #30 "NPE while adding a Library to a module"

Issues: #30
Fixed #28 "Code formatting" by applying IDEA default code formatter

Issues: #28
Fixed #27 "Running the build with IDEA 12.1 jars fails tests"

* added missing reference to PlatformUltraLiteTestFixture
* added missing dependency to idea.jar and trove4j
* upgraded pom.xml to use intellij 12.1.0
* upgraded project.version to 1.0.7
* added changelog link to plugin.xml

Issues: #27
Updated according to pull-request feedback

- updated install-intellij-libs.sh to easily install all JARs in IntelliJ's lib folder
- referenced jars from the lib folder in our pom.xml
- updated README.md

Issues: #31
Fixed #29 "ToolWindow icons should be 13x13 - warning on a console"

- resized sonar.png to 13x13 pixel

Issues: #29
Merge pull request #31 from aheusingfeld/master

Fixed some bugs and updated version