Resolves merge conflicts and adds maven pom.xml

 I've attempted to resolve conflicts with Anwar's reverse_http here, and added support for building via maven. @timwr please take a look when you have a chance, thanks!

Note: to build, you need to add a flag for `android.ndk.path`. I'll update the readme after this lands. You also can use the `new-android-bins` branch of my [fork](https://github.com/jvennix-r7/metasploit-framework) to test, as it has the binaries built from this PR.