Update ImporterTGF.java

[SECURITY] Use HTTPS to resolve dependencies in Maven Build

This fixes a security vulnerability in this project where the `pom.xml`
files were configuring Maven to resolve dependencies over HTTP instead of
HTTPS.
Signed-off-by: NJonathan Leitschuh <Jonathan.Leitschuh@gmail.com>

Corrected TGF Importer to support files without labels

(WIP) Use travis' native homebrew package installation method

Thanks for the request!

* Update Forum URL on string #25
* added space on string #102

Update Gephi plugin URL in README

Add missing file