icon theme tweaks

Get the theme from the icon's screen, and make it rescan if needed.
Pretty sure it doesn't know whether it's needed since Skype icons only
start showing up after ar restart.. but it works fine for others.
quick minimal appindicator patch

Currently supported: icon names and icon theme names, menus. Tooltips do
not appear to work, more research is needed in this department.

This patch also breaks the SNI item_registered D-Bus signal, meaning
less spec coverage. Then again, this signal does not seem to be used by
anything in the wild, and it could easily be made available if needed.
Until then, it's probably just some saved cycles.
add another workaround
workaround for libappindicator
icon name: check for null (Gtk warning)
freedesktop icons support
tooltip text support

All tested applications only seem to set tooltip titles instead of
tooltip text, but the tex is also included. Tooltip icons are not
supported, markup is supported except for <a> (just pumps the text
through Pango Markup parser, which doesn't support <a>). Can't click it
do not cache D-Bus properties

Apparently GDBusObjectProxy loads properties from a cache by default,
only updating values when some D-Bus changed signal arrives. Which never
will in a common case (QSystemTrayIcon).
README: add git as build dependency
SNI.Menu dbusmenu support through libdbusmenu-gtk3
fighting sr.ht markdown parser
fighting sr.ht markdown parser
fork: search in path
updated readme, makefile
README: markdown and more info
version from git describe
README: electron environment hack
maintenance: use constants where possible
--fork option, usage info in README
add VFLAGS to makefile (-g for debug)