Remove netcdf support

Sadly netcdf library is not Apache2 License compatible so we should not package it anymore.

For users who wants to use it, they can add manually [netcdf librairies](http://www.unidata.ucar.edu/software/thredds/current/netcdf-java/) in `plugins/mapper-attachments` dir and they will get the support back.

Closes #84.

pom.xml

@@ -119,6 +119,12 @@
             <artifactId>tika-parsers</artifactId>
             <version>1.5</version>
             <scope>compile</scope>
+            <exclusions>
+                <exclusion>
+                    <groupId>edu.ucar</groupId>
+                    <artifactId>netcdf</artifactId>
+                </exclusion>
+            </exclusions>
         </dependency>
 
         <dependency>