TACHYON-8 [WIP] First drop of Tachyon neo configuration

The PR includes:
-) TACHYON-193
Add new Tachyon properties file configuration.  
Add new code to support Tachyon properties configuration for runtime. 
This will be file based could be overriden via site specific configuration file or override collection in the TachyonConf class.
-) TACHYON-194
Add TachyonConf class to unify all Tachyon configurations.
Use single class TachyonConf to manage the configurations properties as key-value store.

1) we explicitly depend on commons-lang, so no new dependencies are needed.

```
<dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-lang3</artifactId>
      <version>3.0</version>
    </dependency>
```

2) the concern was adding a new lib. Using a function in a existing one doesn't fall under those concerns.