removed Maven 3 warnings

Maven 3 spits out a lot of warnings in the beginning:

#### From
```
$ mvn clean install
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.hectorclient:hector-core:bundle:1.1-2-SNAPSH                                                                           OT
[WARNING] 'build.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.                                                                           plugins:maven-jar-plugin @ org.hectorclient:hector:1.1-2-SNAPSHOT, C:\Users\kpietrzak\Documents\Downloads\hector-master\pom.xml,                                                                            line 258, column 17
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-source-plugin is missing. @ org.hectorclient:hector:                                                                           1.1-2-SNAPSHOT, C:\Users\kpietrzak\Documents\Downloads\hector-master\pom.xml, line 245, column 11
[WARNING] The expression ${pom.version} is deprecated. Please use ${project.version} instead.
[WARNING] The expression ${pom.version} is deprecated. Please use ${project.version} instead.
[WARNING] The expression ${pom.version} is deprecated. Please use ${project.version} instead.
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.hectorclient:hector-object-mapper:jar:3.1-07                                                                           -SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-source-plugin is missing. @ org.hectorclient:hector:                                                                           1.1-2-SNAPSHOT, C:\Users\kpietrzak\Documents\Downloads\hector-master\pom.xml, line 245, column 11
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.hectorclient:hector-test:jar:1.1-2-SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-source-plugin is missing. @ org.hectorclient:hector:                                                                           1.1-2-SNAPSHOT, C:\Users\kpietrzak\Documents\Downloads\hector-master\pom.xml, line 245, column 11
[WARNING] The expression ${pom.version} is deprecated. Please use ${project.version} instead.
[WARNING] The expression ${pom.version} is deprecated. Please use ${project.version} instead.
[WARNING]
[WARNING] Some problems were encountered while building the effective model for org.hectorclient:hector:pom:1.1-2-SNAPSHOT
[WARNING] 'build.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.                                                                           plugins:maven-jar-plugin @ line 258, column 17
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-source-plugin is missing. @ line 245, column 11
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
```

#### To
```
$ mvn install
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] hector
[INFO] test
[INFO] hector-core
[INFO] hector-object-mapper
```

So I think I got rid of all of them.