remove virtualbox packages during the procedure

also mention the segfaults that keeping virtualbox around can cause:
this can be very confusing at first. making people remove virtualbox
will reduce confusion.
updated troubleshooting.md
added link to firefox sync
Merge remote-tracking branch 'lelutin/feature/vagrant_no_virtualbox'
added stunnel section for MX and couch nodes
added note on how pond does routing
remove '#leap-dev' from communication channels, since we agreed on using
\#leap until that gets too noisy
updated project ideas
Add "Dynamic OpenVPN configuration" in Android section of project-ideas

Edit difficulty of OpenVPN fail closed on Android
Vanity edit for meanderingcode nick :P
Remove some user docs in favor of dl.bitmask.net

Also:
- Remove link to readthedocs.
- Remove advanced instructions in favor of Hacking section.
Update Hacking instructions.

Also:
- remove manual copy of files already done by bitmask.
- update dependency installation instructions.
Add automagic helper script.
Update testing section.

- Update #leap channel.
- Remove unused instructions.
- Point to Hacking section instead of duplicate the docs.
Fix style and section name.
Update supported OSs.
fix address of IRC server
clarify that you should not run any commands as a privileged user,
unless it has 'sudo' indicated (#4473)
Update instructions for developers.

- Some of them were get from bitmask_client docs.

This closes #4185.
Update databases list, add tapicero to misc
Corretions and update to pt-br translation.