[LINUX] build a .tar.gz to be unpacked anywhere.

This is the easiest way for non-Debian systems to run Brackets without
creating a package for each distribution. The output can also be used to
ease packaging for other systems (hopefully).
Linux .tar.gz script should clean up after itself.
Linux .tar.gz: support more mimetypes via brackets.desktop

Now supports:
text/html
text/css
text/javascript
application/javascript
Linux uninstall script: optionally remove Brackets config.

When passed the -c parameter, uninstall.sh will remove the user's local
Brackets configuration.
Call xdg-desktop-menu for GUIs not monitoring ~/.local.

Only seems to be Unity that is not watching ~/.local/share/applications
right now.
Augment README.md.
When possible, automatically symlink to libudev.so.0

Only works on Ubuntu, Fedora, SUSE, and Arch.
Fix up some Markdown rendering errors in README.md.
Merge pull request #433 from radicaled/linux_targzip

[LINUX] build a .tar.gz to be unpacked anywhere.