Revert "Don't allow TextFile to be initialised with null inputs"

This reverts commit c8f4552cb7.

Change-Id: I676f8529ed4f9a245893389e9ac35d58c92a53e5
Reviewed-on: http://gerrit.dmdirc.com/917
Automatic-Compile: Chris Smith <chris@dmdirc.com>
Reviewed-by: Chris Smith <chris@dmdirc.com>

src/com/dmdirc/util/TextFile.java

      * @since 0.6.3m1
      */
     public TextFile(final File file, final Charset charset) {
-        if (file == null) {
-            throw new NullPointerException("file");
-        }
-
         this.file = file;
         this.charset = charset;
     }
      * @since 0.6.3m1
      */
     public TextFile(final InputStream is, final Charset charset) {
-        if (is == null) {
-            throw new NullPointerException("is");
-        }
-
         this.is = is;
         this.charset = charset;
     }